Abstract:
A method for processing a call in an asynchronous mobile communication system including an asynchronous mobile station, an asynchronous radio network, wherein a synchronous core network is interlocked, includes the steps of: setting up the call in case a calling call message is generated in the mobile station; establishing a channel between the asynchronous mobile station and the asynchronous radio network; handling basic information for assigning a radio resource; performing a cipher establishment; establishing the radio resource; performing a configuration for a service; and transmitting a phone call stand-by message to a user.

Description:
FIELD OF THE INVENTION 
   This invention relates to a method for processing a handoff and a call in an asynchronous mobile communication system, accented in an International Mobile Telecommunication-2000 (IMT-2000) system; and, more particularly, to a method for processing the handoff and the call in the asynchronous mobile communication system coupled to a synchronous core network. 
   DESCRIPTION OF THE PRIOR ART 
   In a conventional synchronous mobile communication system, a synchronous radio network, for example; a code division multiple access-2000 (CDMA-2000) radio network, is coupled to a synchronous mobile station and a synchronous core network (CN). 
   Also, in a conventional asynchronous mobile communication system, an asynchronous radio network, for example, an universal mobile telecommunication system (UMTS) Terrestrial Radio Access Network (UTRAN) is coupled to an asynchronous mobile station and an asynchronous core network.  FIG. 1  shows core network interface architectures of the conventional synchronous/asynchronous mobile communication system as mentioned above. 
     FIG. 1A  shows the core network interface architecture of the conventional synchronous mobile communication system. In this drawing, the reference numeral  11  denotes a synchronous mobile station,  12  denotes a synchronous radio network (i.e., a code division multiple access-2000 (CDMA-2000) radio network) which performs a data interfacing operation with the synchronous mobile station  11  and includes a synchronous base transceiver station/base station controller (BTS/BSC), and  13  denotes a synchronous core network which is connected to the synchronous radio network  12  and includes a synchronous mobile services switching center (MSC). 
   In the above core network interface architecture of the conventional synchronous mobile communication system, the synchronous mobile station  11  can be connected to only the synchronous radio network  12  as well known to one skilled in the art, which is in turn connected to the synchronous core network  13 , thereby allowing the synchronous mobile station  11  to be interfaced with only the synchronous core network  13 . 
     FIG. 1B  shows the core network interface architecture of the conventional asynchronous mobile communication system. In this drawing, the reference numeral  21  denotes an asynchronous mobile station,  22  denotes an asynchronous radio network (i.e., a UTRAN) which includes a base transceiver station (BTS) and a radio network controller (RNC), and  23  denotes an asynchronous core network which includes an asynchronous mobile services switching center (MSC) connected to the UTRAN  22 . 
   In the above core network interface architecture of the conventional asynchronous mobile communication system, the asynchronous mobile station  21  is connected to the asynchronous radio network  22  (i.e., UTRAN) which is in turn connected to the asynchronous core network  23 , thereby allowing the asynchronous mobile station  21  to perform a data interfacing operation with the asynchronous core network  23 . 
     FIG. 2  shows layered protocol structures of the conventional synchronous/asynchronous mobile communication system as mentioned above. 
     FIG. 2A  shows the layered protocol structure of the conventional synchronous mobile communication system. In this drawing, the reference numeral  30  denotes a synchronous mobile station,  40  a synchronous radio network and  50  a synchronous core network connected to the synchronous radio network  40 . 
   The synchronous mobile station  30  comprises a layer  3   31 , a layer  2   35  and a layer  1   36 . The layer  3   31  includes a synchronous call control (CC) entity  32  for management of a call and a synchronous mobility management (MM) entity  33  for management of a mobility. 
   The layer  3   31  is a network layer which includes the following sub layers: a synchronous radio resource (RR) sub layer  34 , a synchronous call control (CC) entity  32  and a mobility management (MM) entity  33 . In synchronous systems, the synchronous RR sub layer  34  is not apparently separated from the others in the layer  3   31 . 
   The RR sub layer  34  offers data transfer services on primitives to a lower layer (RLC sub layer) and handles control plane signaling of the layer  3   31  between a mobile station (MS) and a synchronous radio network. The RR sub layer  34  manages a radio resource. Also, the RR sub layer  34  assigns/re-configures/releases the radio resource to UE/UTRAN. 
   The CC entity  32  handles layer call control signaling between the MSs and the synchronous radio network. 
   The MM entity  33  handles layer  3  mobility management signaling of layer  3  between the MSs and the synchronous radio network. 
   The layers  3  to  1   31 ,  35  and  36  in the synchronous mobile station  30  communicate with corresponding layers  41 ,  45  and  46  in the synchronous radio network  40 . 
   The synchronous radio network  40  comprises a layer  3   41 , a layer  2   45  and a layer  1   46 . The layers  3  to  1  in the synchronous radio network  40  correspond respectively to those in the synchronous mobile station  30 . 
   The layers  3  to  1   41 ,  45  and  46  in the synchronous radio network  40  communicate with corresponding layers  31 ,  35 ,  36 ,  51 ,  55  and  56  in the synchronous mobile station and the synchronous core network  50 . 
   The synchronous core network  50  comprises a layer  3   51 , a layer  2   55  and a layer  1   56 . The layers  3  to  1  in the synchronous radio network  50  correspond respectively to those in the synchronous mobile station  30 . The layers  3  to  1   51 ,  55  and  56  in the synchronous core network  50  communicate with corresponding layers  41 ,  45  and  46  in the synchronous radio network  40 . 
   In the conventional synchronous mobile station and radio network as the layered protocol structure, the synchronous mobile station  30  receives a Sync channel message from the synchronous radio network  40  over a Sync channel and acquires information necessary to its connection to the synchronous core network  50 , including information related to the synchronous core network  50  and information about the synchronous radio network  40 , from the received Sync channel message. 
   In other words, for interfacing with the synchronous ANSI-41 network via the synchronous radio network, the synchronous mobile station acquires system information (i.e., information related to the radio network and core network) through a system determination sub-state, a pilot channel acquisition sub-state, a Sync channel acquisition sub-state and a timing changing sub-state after it is powered on. 
     FIG. 2B  shows the layered protocol structure of the conventional asynchronous mobile communication system. In this drawing, the reference numeral  60  denotes an asynchronous mobile station,  70  a UTRAN and  80  an asynchronous core network. 
   The asynchronous mobile station  60  comprises a layer  3   61 , a layer  2   65  and a layer  1   66 . In particular, the layer  3   61  includes a non-access stratum (NAS) part and an access stratum (AS) part. The NAS part includes an asynchronous call control (CC) part  62  for management of a call and an asynchronous mobility management (MM) part  63  for management of a mobility. The AS part includes an asynchronous radio resource control (RRC) part  64 . In the asynchronous system, the asynchronous RRC sub layer is apparently separated from the NAS part. Functions of the asynchronous RRC sub layer are the same as those of the synchronous RR sub layer. 
   The UTRAN  70  comprises a layer  3   71 , a layer  2   73  and a layer  1   74 . The layer  3   71  of the UTRAN  70  has no NAS part having asynchronous CC part and asynchronous MM part. The layers  3  to  1  of the UTRAN  70  are connected and correspond respectively to those in the asynchronous mobile station  60  and those in the asynchronous core network  80 . However, since the UTRAN  70  does not have the NAS part, i.e., the asynchronous CC part and the asynchronous MM part, the NAS parts of the asynchronous mobile station  60  and the asynchronous core network  80  are coupled to each other not through the UTRAN  70 . 
   The asynchronous core network  80  comprises a layer  3   81  having an NAS part connected to that of the asynchronous mobile station  60  and an AS part, a layer  2   85  and a layer  1   86  connected respectively to those in the UTRAN  70 . The NAS part comprises an asynchronous CC part  82  for management of a call and an asynchronous MM part  83  for management of a mobility. 
   Functions of the layer  3  to  1  of the asynchronous system are similar with those of the synchronous system except for an operating type. Therefore, detailed description of the layer  3  to  1  will be skipped. 
   The more detailed descriptions about layered protocol structures are well taught in 3 rd  Generation Partnership Project (3GPP), Technical Specification Group (TSG)—Radio Access Network (RAN): 3G TS25.301 (Radio Interface Protocol Architecture), 3G TS25.302 (Services provided by the physical layer), 3G TS25.321 (MAC Protocol Specification), 3G TS25.322 (RLC Protocol Specification) and 3G TS25.331 (RRC Protocol Specification) in detail. 
   In the conventional asynchronous mobile station and radio network having the layered protocol structure, the asynchronous mobile station  60  receives a system information message from the UTRAN  70  over a broadcast control channel (BCCH) and acquires information necessary to its connection to the asynchronous core network  80 , including information related to the asynchronous core network  80  and information about the UTRAN  70 , from the received system information message. 
   In the next-generation mobile telecommunication system such as the IMT-2000 system, either the GSM-MAP network used in the above conventional asynchronous mobile communication system or the ANSI-41 network used in the above conventional synchronous mobile communication system should be employed as a core network in order to perform international roaming in a synchronous or asynchronous mobile communication system of an IMT-2000 system. 
   According to network deployment scenarios, the IMT-2000 system can have the following four interface architectures; first: synchronous mobile station—synchronous radio network—synchronous ANSI-41 network, second: synchronous mobile station—synchronous radio network—asynchronous GSM-MAP network, third: asynchronous mobile station—asynchronous radio network—synchronous ANSI-41 network and fourth: asynchronous mobile station—asynchronous radio network—asynchronous GSM-MAP network. 
     FIG. 3  shows core network interface architectures of the next-generation mobile communication system such as the IMT-2000 system. 
     FIG. 3A  shows a synchronous ANSI-41 core network interface architecture of a hybrid type synchronous radio network. In this drawing, the reference numeral  100  denotes a hybrid type synchronous mobile station,  110  a hybrid type synchronous radio network, and  120  a synchronous core network which includes a synchronous mobile services switching center (MSC). 
     FIG. 3B  shows an asynchronous GSM-MAP core network interface architecture of the hybrid type synchronous radio network. In this drawing, the reference numeral  100  denotes a hybrid type synchronous mobile station,  110  a hybrid type synchronous radio network, and  130  an asynchronous core network which includes an asynchronous MSC. 
     FIG. 3C  shows an asynchronous GSM-MAP core network interface architecture of a hybrid type asynchronous radio network. In this drawing, the reference numeral  210  denotes a hybrid type asynchronous mobile station,  220  denotes a hybrid type UTRAN which is a hybrid type asynchronous radio network, and  230  denotes an asynchronous core network which is connected to the hybrid type UTRAN  220  and includes an asynchronous MSC. 
     FIG. 3D  shows a synchronous ANSI-41 core network interface architecture of the hybrid type asynchronous radio network. In this drawing, the reference numeral  210  denotes a hybrid type asynchronous mobile station,  220  denotes a hybrid type UTRAN which is a hybrid type asynchronous radio network, and  240  denotes a synchronous core network which is connected to the hybrid type UTRAN  220  and includes a synchronous MSC. 
   In order to be operable adaptively to the above four interface architectures, each of the hybrid type synchronous and asynchronous mobile stations in the next-generation mobile communication system has both asynchronous CC and MM protocol entities serving for the GSM-MAP core network and synchronous CC and MM protocol entities serving for the ANSI-41 core network at the layer  3  in the protocol stack structure, which is a different from each of the conventional synchronous and asynchronous mobile stations. 
     FIG. 4  shows layered protocol structures of the next-generation mobile communication system. 
     FIG. 4A  shows the layered protocol structure of a hybrid type synchronous mobile station, a hybrid type synchronous radio network and the synchronous ANSI-41 core network. In this drawing, the reference numeral  100  denotes a hybrid type synchronous mobile station,  110  denotes a hybrid type synchronous radio network, and  120  denotes an ANSI-41 core network which is a synchronous core network connected to the hybrid type synchronous radio network  110 . 
   The hybrid type synchronous mobile station  100  comprises a layer  3   101 , a layer  2   107  and a layer  1   108 . The layer  3   101  comprises a synchronous CC part  102 , a synchronous MM part  103 , an asynchronous CC part  104 , an asynchronous MM part  105  and a synchronous radio resource part  106 . The hybrid type synchronous mobile station  100  selectively makes a CC/MM protocol active according to a core network operating type. Information for identifying the core network operating type is given to the hybrid type synchronous mobile station  100 . 
   For example, if the hybrid type synchronous mobile station  100  is currently connected to the ANSI-41 core network  120 , the layer  3   101  therein activates protocols of the synchronous CC part  102  and synchronous MM part  103  to perform a message interfacing operation with the ANSI-41 core network  120 . 
   The hybrid type synchronous radio network  110  comprises a layer  3   111 , a layer  2   115  and a layer  1   116 , which activates their protocols corresponding respectively to those in the hybrid type synchronous mobile station  100  and those in the ANSI-41 core network  120  to transmit and receive messages. The layer  3   111  includes a synchronous CC part  112 , a synchronous MM part  113  and a synchronous RR part  114 . 
   The ANSI-41 core network  120  comprises a layer  3   121 , a layer  2   125  and a layer  1   126 . The layer  3   121  comprises a synchronous CC part  122 , a synchronous MM part  123  and a synchronous RR part  124 . 
   In  FIG. 4B , the reference numeral  100  denotes a hybrid type synchronous mobile station,  110  denotes a hybrid type synchronous radio network, and  130  denotes a GSM-MAP core network which is an asynchronous core network. 
   The hybrid type synchronous mobile station  100  comprises a layer  3   101  having a NAS part and an AS part, a layer  2   107  and a layer  1   108 . The NAS part includes a synchronous CC part  102 , a synchronous MM part  103 , an asynchronous CC part  104  and an asynchronous MM part  105 . The AS part includes a synchronous RR part  106 . The hybrid type synchronous mobile station  100  selectively makes a CC/MM protocol active according to a core network operating type. 
   For example, if the hybrid type synchronous mobile station  100  is currently connected to the GSM-MAP core network  130 , the layer  3   101  therein activates protocols of the asynchronous CC part  104  and asynchronous MM part  105  to perform a message interfacing operation with the GSM-MAP core network  130 . 
   The hybrid type synchronous radio network  110  comprises a layer  3   111  having a NAS part and an AS part, a layer  2   115  and a layer  1   116 , which activate their protocols corresponding respectively to those in the hybrid type synchronous mobile station  100  and those in the GSM-MAP core network  130  to transmit and receive messages. 
   The GSM-MAP core network  130  comprises a layer  3   131  having a NAS part and an AS part, a layer  2   135  and a layer  1   136 . The NAS part includes an asynchronous CC part  132  and an asynchronous MM part  133 . The AS part includes an asynchronous RRC part  134 . 
   The layers  3  to  1  of the hybrid type synchronous radio network  110  are connected and correspond respectively to those in the hybrid type synchronous mobile station  100  and those in the asynchronous core network  130 . However, the NAS parts of the hybrid type asynchronous mobile station  100  and the asynchronous core network  130  are coupled to each other not through the hybrid type synchronous mobile station  110 . 
     FIG. 4C  shows layered protocol structures of a hybrid type asynchronous mobile station, a hybrid type asynchronous radio network and a synchronous ANSI-41 core network. In this drawing, the reference numeral  210  denotes a hybrid type asynchronous mobile station,  220  denotes a hybrid type UTRAN which is a hybrid type asynchronous radio network, and  230  denotes an ANSI-41 core network connected to the hybrid type UTRAN  220 . 
   The hybrid type asynchronous mobile station  210  comprises a layer  3   211 , a layer  2   217  and a layer  1   218 . The layer  1  includes a synchronous CC part  212 , a synchronous MM part  213 , an asynchronous CC part  214 , an asynchronous MM part  215  and asynchronous RRC part  216  and selectively activates a synchronous CC/MM protocol or an asynchronous CC/MM protocol. 
   For example, if the hybrid type asynchronous mobile station  210  is currently connected to the ANSI-41 core network  230 , the layer  1  therein activates a protocol between the synchronous CC part  212  and synchronous MM part  213  to perform a message interfacing operation with the ANSI-41 core network  230 . 
     FIG. 4D  shows layered protocol structures of a hybrid type asynchronous mobile station, a hybrid type asynchronous radio network and an asynchronous GSM-MAP core network. In this drawing, the reference numeral  210  denotes a hybrid type asynchronous mobile station,  220  denotes a hybrid type UTRAN which is a hybrid type asynchronous radio network, and  240  denotes an asynchronous GSM-MAP core network connected to the hybrid type UTRAN  220 . 
   The hybrid type asynchronous mobile station  210  comprises a layer  3   211  having a NAS part and an AS part, a layer  2   217  and a layer  1   218 . The NAS part includes a synchronous CC part  212 , a synchronous MM part  213 , an asynchronous CC part  214  and an asynchronous MM part  215  and selectively activates a synchronous CC/MM protocol or an asynchronous CC/MM protocol. The AS part includes an asynchronous RRC part  216 . 
   The hybrid type asynchronous radio network  220  comprises a layer  3   221  having a NAS part and an AS part, a layer  2   225  and a layer  1   226 , which activate their protocols corresponding respectively to those in the hybrid type asynchronous mobile station  210  and those in the GSM-MAP core network  240  to transmit and receive messages. 
   The GSM-MAP core network  240  comprises a layer  3   241  having a NAS part and an AS part, a layer  2   245  and a layer  1   246 . The NAS part includes an asynchronous CC part  242  and an asynchronous MM part  243 . The AS part includes an asynchronous RRC part  244 . 
   For example, if the hybrid type asynchronous mobile station  210  is currently connected to the GSM-MAP core network  240 , the NAS part therein activates protocols of the asynchronous CC part  214  and asynchronous MM part  215  to perform a message interfacing operation with the GSM-MAP core network  240 . 
   The layers  3  to  1  of the hybrid type asynchronous radio network  220  are connected and correspond respectively to those in the hybrid type synchronous mobile station  210  and those in the asynchronous core network  240 . However, the NAS parts of the hybrid type asynchronous mobile station  210  and the asynchronous core network  240  are coupled to each other not through the hybrid type asynchronous mobile station  220 . 
   As described above, IMT-2000 system includes four interlocking structures, and thus interface specifications corresponding to each interlocking structure are required. That is, for processing a handoff and a call in the synchronous/asynchronous mobile communication system, an interface protocol of synchronous/asynchronous communication mode is required, respectively. 
   In the asynchronous mobile communication system, Air-Interface refers to an interface between the synchronous mobile station and the synchronous radio network, and a protocol such a TIA/EIA/IS-2000 is used for the Air-interface. A-Interface refers to an interface between the synchronous radio network and the synchronous ANSI-41 core network, and a protocol such as 3 Generation Interoperability Specification (3G-IOS) is used for the A-interface. Each of TIA/EIA/IS-2000 and 3G-IOS is an international standard communication protocol used for Air-interface and A-interface of the IMT-2000 system of the synchronous communication mode, but is not available for the asynchronous communication mode. When processing a handoff and a call in the conventional synchronous mobile communication system having the above interface, it is required to process the handoff and the call as defined in the international standard synchronous communication protocol, and to mutually exchange messages and parameters defined in the international standard synchronous communication protocol. That is, the message and the parameter defined in the international standard communication protocol TIA/EIA/IS-2000, are mutually exchanged through the A-interface between the synchronous mobile station and the synchronous radio network. And, the A-interface between the synchronous radio network and the ANSI-41 network uses a method for processing a handoff and a call as defined in the international standard communication protocol 3G-IOS. The message and the parameter are mutually exchanged through the A-interface. 
   In the asynchronous mobile communication system, Air-interface refers to an interface between the asynchronous mobile station and the asynchronous radio network, and a protocol, commonly called, Asynchronous Communication Air-Interface is used between them. A-Interface refers to interface between the asynchronous radio network and the asynchronous GSM-MAP core network, and a protocol such as a Radio Access Network Application Part (RANAP) is used between them. Each of Asynchronous Communication Air-Interface and RANAP is an international standard communication protocol used for the Air-interface and the A-interface of the asynchronous IMT-2000 system, but is not available for the synchronous communication mode. 
   When processing a handoff and a call in the conventional asynchronous mobile communication system having the above interface, it is required to process the handoff and the call as defined in the international standard asynchronous communication protocol, and to mutually exchange a message and a parameter defined in the international standard asynchronous communication protocol. That is, the message and the parameter defined in the international standard communication protocol Asynchronous Communication Air-Interface are mutually exchanged through Air-interface between the asynchronous mobile station and the asynchronous radio network. And, the A-interface between the asynchronous radio network and the GSM-MAP network uses a method for processing the handoff and the call, as defined in the international standard communication protocol RANAP. The message and the parameter are mutually exchanged through the A-interface. 
   As can be seen from above, in the asynchronous IMT-2000 system, an international communication protocol defined for the asynchronous communication mode should be used for good processing of the handoff and the call. That is, the international standard communication protocol commonly called Asynchronous Communication Air-Interface should be used for the Air-Interface, and the communication protocol called RANAP should be used for the A-Interface. 
   However, in cases where the asynchronous mobile station, the asynchronous radio network and the synchronous ANSI-41 core network are coupled to each other, the international communication protocol for the asynchronous communication mode is unusable. In other words, the international communication protocol of Asynchronous Communication Air-Interface should be used for the Air-Interface between the asynchronous mobile station and the asynchronous radio network, and the international communication protocol of 3G-IOS should be used for the A-Interface between the asynchronous radio network and the synchronous core network. 
   In conclusion, the conventional international communication protocol of the asynchronous communication mode does not take the Air-Interface and A-Interface communication protocol of the synchronous communication mode into consideration. 
   Thus, the problem is that interlocking is impossible, in case the synchronous ANSI-41 core network is connected to the asynchronous radio network in the asynchronous communication system. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a method for processing a call and a handoff in an asynchronous mobile communication system including an asynchronous mobile station and an asynchronous radio network in case a synchronous core network is connected to the asynchronous mobile communication system. 
   In accordance with an aspect of the present invention, there is provided a method for processing a call in an asynchronous mobile communication system including an asynchronous mobile station, an asynchronous radio network, wherein a synchronous core network is interlocked, comprising the steps of: a) setting up the call in case a calling call message is generated in the mobile station; b) establishing a channel between the asynchronous mobile station and the asynchronous radio network; c) handling basic information for assigning a radio resource; d) performing a cipher establishment; e) establishing the radio resource; f) performing a configuration for a service; and g) transmitting a phone call stand-by message to a user. 
   In accordance with another aspect of the present invention, there is provided a method for processing a handoff in an asynchronous mobile communication system including an asynchronous mobile station, a source asynchronous radio network and a target radio network, wherein a synchronous core network is interlocked, the method comprising the steps of: a) determining to handoff; b) selecting the target radio network for the handoff; c) in response to a handoff request, providing information related to the handoff, thereby completing a preparation for the handoff; d) establishing a connection between the asynchronous mobile station and the target radio network, thereby completing the handoff; and e) disconnecting the communication between the asynchronous mobile station and the source asynchronous radio network. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, in which: 
       FIG. 1A  is a pictorial representation illustrating a conventional structure of a synchronous mobile communication system interlocking with a synchronous core network; 
       FIG. 1B  is a pictorial representation of conventional structuring of an asynchronous mobile communication system interlocking with an asynchronous core network; 
       FIG. 2A  is a diagram representing protocol structures of each section in the synchronous mobile communication system; 
       FIG. 2B  is a diagram representing protocol structures of each section in the asynchronous mobile communication system; 
       FIG. 3A  is a pictorial representation of structure of interlocking with a synchronous ANSI-41 core network in a synchronous mobile communication system; 
       FIG. 3B  is a pictorial representation of structure of interlocking with an asynchronous GSM-MAP core network in a synchronous mobile communication system; 
       FIG. 3C  is a pictorial representation of structure of interlocking with an asynchronous GSM-MAP core network in an asynchronous mobile communication system; 
       FIG. 3D  is a pictorial representation of structure of interlocking with a synchronous ANSI-41 core network in an asynchronous mobile communication system; 
       FIG. 4A  is a schematic diagram representing protocol layers structure in the synchronous mobile communication system interlocking with the ANSI-41 core network; 
       FIG. 4B  is a schematic diagram representing protocol layers structure in the synchronous mobile communication system interlocking with an asynchronous core network; 
       FIG. 4C  is a schematic diagram representing protocol layers structure in the asynchronous mobile communication system interlocking with a synchronous ANSI-41 core network; 
       FIG. 4D  is a schematic diagram representing protocol layers structure in the asynchronous mobile communication system interlocking with an asynchronous GSM-MAP core network; 
       FIG. 5  is a pictorial representation of a whole interlocking structure, in case a core network is an ANSI-41 network in accordance with the present invention; 
       FIG. 6  is a pictorial representation interface protocols in a wired area and a radio area in accordance with the present invention; 
       FIGS. 7A and 7B  are flow diagrams representing a method for processing a call in the asynchronous mobile communication system in accordance with the present invention; 
       FIG. 8  represents a Call Clearing Flow initiated by the asynchronous mobile station, in case the synchronous ANSI-41 core network is coupled to the asynchronous radio network in the asynchronous mobile communication system; 
       FIG. 9  is a flow diagram representing a method for processing a call clearing, in case the Mobile Switching Center (MSC) of the synchronous core network initiates a call-clearing signal in the asynchronous mobile communication system; 
       FIGS. 10A and 10B  are flow diagrams representing a method for processing a handoff in the asynchronous mobile communication system in accordance with the present invention, wherein a synchronous core network is interlocked with a source asynchronous radio network and a target asynchronous radio network; 
       FIGS. 11A and 11B  are flow diagrams representing a method for processing handoff in the asynchronous mobile communication system in accordance with the present invention, wherein a synchronous core network is interlocked with a source asynchronous radio network and a target synchronous radio network; 
       FIGS. 12A and 12B  are flow diagrams representing a method for processing a handoff in the asynchronous mobile communication system, wherein a synchronous core network is interlocked with a source synchronous radio network and a target asynchronous radio network; and 
       FIGS. 13A and 13B  are flow diagrams representing a method for processing a handoff in the asynchronous mobile communication system in accordance with the present invention, wherein a synchronous core network is interlocked with a source asynchronous radio network and an analog radio network. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, preferred embodiments in accordance with the present invention will be described hereinafter in detail referring to the accompanying drawings. 
     FIG. 5  is a pictorial representation of a whole interlocking structure, in case a core network is an ANSI-41 network in accordance with the present invention. 
   A reference numeral  300  denotes an asynchronous radio network in the asynchronous mobile communication system. A reference numeral  400  denotes a synchronous core network connected to the asynchronous radio network  300 . A reference numeral  500  denotes an analog radio network capable of being connected to the synchronous core network  400 . A reference numeral  600  denotes a synchronous radio network capable of being connected to the synchronous core network  400 . 
     FIG. 6  is a pictorial representation of interface protocols in a wired area and a radio area. 
   Reference numerals  310 ,  300  and  400  denote an asynchronous mobile station, an asynchronous radio network and a synchronous core network, respectively. 
   In this interlocking structure, an interface protocol for the radio area, that is, the interface protocol between the asynchronous mobile station  310  and the asynchronous radio network  300  should follow an Asynchronous Communication Air-Interface of a conventional international communication protocol for asynchronous communication mode. An interface for wire service area, that is, the interface protocol between the asynchronous radio network  300  and the synchronous core network  400  should follow a 3G-IOS of a conventional international communication protocol. 
   As can be seen from above, a new type of processing method for a handoff and a call is required in the interlocking structure having different communication modes. 
   In the present invention, there is provided a method of processing a handoff and a call capable of processing a handoff and a call in the interlocking structure having the different communication modes. 
   Embodiment 1 
     FIGS. 7A to 7C  are flow charts representing a method for processing a call in the asynchronous mobile communication system in accordance with the present invention. 
   Reference numerals  710 ,  711 ,  712  and  713  denote an asynchronous mobile station, a call control (CC) entity, a Mobility Management (MM) entity and a radio resource controller (RRC), respectively. The asynchronous mobile station includes the call control (CC) entity, the Mobility Management (MM) entity and a radio resource controller (RRC). 
   Reference numerals  720  and  721  denote an asynchronous radio network UTRAN and a radio resource controller (RRC) included in the UTRAN, respectively. 
   Reference numerals  730 ,  731  and  732  denote a synchronous ANSI-41 core network, a Mobility Management (MM) entity and a call control entity, respectively. A Mobility Switching Center (MSC) in the synchronous core network  730  includes the Mobility Management (MM) entity  731  and the call control (CC) entity  732 . 
   As shown in  FIGS. 7A to 7C , this interlocking structure is the structure of interlocking the synchronous core network and the asynchronous radio network in the asynchronous mobile communication system, and hereinafter, the method for processing the call in this structure will be described. 
   At step S 1 , the call control (CC) entity included in a Non Access Stratum (NAS) of the asynchronous mobile station  710  transmits an ‘Origination’ message to a radio resource controller (RRC) included in an Access Stratum (AS) of the asynchronous mobile station by using a Primitive. The Primitive represents ‘mobile station (MS) Side Initiated Connection Establishment Request’ message of a Dedicated Control Service Access Point (DC-SAP) provided by the Access Stratum (AS). Receiving the ‘Origination’ message, a Call Origination is started. 
   At step S 2 , the RRC in the asynchronous mobile station that receives the ‘Origination’ message should make a connection with the RRC in the asynchronous radio network  720  having a base transceiver station which is also is called a Node B and a base station controller which is also called a Radio Network Controller. At this time, a Dedicated Control Channel (DCCH) can be used. Consequently, the RRC in the asynchronous mobile station transmits a ‘RRC Connection Request’ message to the RRC in the asynchronous radio network  720  and requests ‘RRC Connection’. 
   At step S 3 , the RRC  721  in the asynchronous radio network  720  that receives the ‘RRC Connection Request’ message from the RRC  713  in the asynchronous mobile station  710  performs RRC connection by using information contained in the asynchronous mobile station. After that, through an ‘RRC Connection Setup’ message, the RRC  721  informs the asynchronous mobile station that an RRC connection is completed, and provides information about the DCCH to the asynchronous mobile station  710 . The DCCH is co-used by the asynchronous radio network  720  and the asynchronous mobile station  710 . 
   At step S 4 , after receiving the ‘RRC Connection Setup’ message from the asynchronous radio network, the RRC in the asynchronous mobile station stores information about the DCCH to be used by itself, and establishes the DCCH. And then, the RRC in the asynchronous mobile station transmits information about the capability of the asynchronous mobile station to the RRC in the asynchronous radio network through a ‘UE Capability Information’ message. 
   At step S 5 , after receiving the ‘UE Capability Information’ message from the RRC  713  in the asynchronous mobile station, the RRC  721  in the asynchronous radio network stores information about capability of the asynchronous mobile station and transmits a ‘UE Capability Confirm’ message to the RRC  713  in the asynchronous mobile station. 
   At step S 6 , after receiving the ‘UE Capability Confirm’ message from the RRC  721  in the asynchronous radio network, the RRC  713  in the asynchronous mobile station transmits an ‘Origination’ message through an ‘Initial ’ ‘Initial Direct Transfer’ message to the RRC  721  in the asynchronous radio network. The ‘Initial Direct Transfer’ message is defined in the RRC protocol, as used to transmit a protocol entity included in the NAS between the RRC  713  in the asynchronous mobile station and the RRC  721  in the asynchronous radio network. That is, the ‘Origination’ message, which is included as a portion of the parameters in the ‘Initial Direct Transfer’ message, is transmitted. 
   At step S 7 , after receiving the ‘Initial Direct Transfer’ message from the RRC  713  in the asynchronous mobile station, the RRC  721  in the asynchronous radio network selects and analyzes the ‘Origination’ message from the received message, and then stores necessary information. By referring to the received ‘Origination’ message, the RRC  721  in the asynchronous radio network transmits a ‘CM Service Request’ message to the synchronous core network. The ‘CM Service Request’ message informs that a ‘Call Origination’ message arrived from the synchronous mobile station. 
   At step S 8 , after receiving the ‘CM Service Request’ message from the asynchronous radio network  720 , the synchronous core network stores information about the asynchronous mobile station requesting the ‘Call Origination’, information about the asynchronous mobile station to be called and a lot of information about service to be requested, et al.,. The synchronous core network transmits information required to assign a wire resource by which the asynchronous radio network can communicate with the synchronous core network; and a ‘Assignment Request’ message ordering to assign a radio resource by which the asynchronous radio network can communicate with the asynchronous mobile station, to the asynchronous radio network. 
   At step S 9 , after receiving the ‘Assignment Request’ message from the synchronous core network, the asynchronous radio network establishes the wire resource by which it communicates with the synchronous core network, and performs a process of assigning the radio resource by which it communicates with the asynchronous mobile station. In order to assign the radio resource, the RRC in the asynchronous radio network transmits a ‘Ciphering Mode Command’ message having information of ciphering for data security, which the asynchronous mobile station transmits during a phone call through the ‘Downlink Direct Transfer’ message to the RRC in the asynchronous mobile station. 
   At step S 10 , after receiving the ‘Ciphering Mode Command’ message through the ‘Downlink Direct Transfer’ message from the RRC in the asynchronous radio network, the RRC in the asynchronous mobile station transmits this information through the primitive of ‘Data Transfer Indication’ provided by the DC-SAP to the mobility management (MM) entity included in the NAS of the asynchronous mobile station. 
   At step S 11 , after receiving the ‘Ciphering Mode Command’ message from the RRC in the asynchronous mobile station, the Mobility Management (MM) entity in the asynchronous mobile station stores the information about ciphering, and transmits a ‘Ciphering Mode Complete’ message through the primitive of ‘Data Transfer Request’ provided by the DC-SAP to the RRC  713  in the asynchronous mobile station. 
   At step S 12 , after receiving the ‘Ciphering Mode Complete’ message from the MM entity in the asynchronous mobile station, the RRC  713  in the asynchronous mobile station transmits the ‘Ciphering Mode Complete’ message through the ‘Uplink Direct Transfer’ message to the RRC  721  in the asynchronous radio network. 
   At step S 13 , after receiving the ‘Ciphering Mode Complete’ message from the MM entity in the asynchronous mobile station, the RRC in the asynchronous radio network is informed that establishment of ciphering is completed, and transmits a ‘Channel Assignment’ message through the ‘Downlink Direct Transfer’ message to the RRC  713  in the asynchronous mobile station, in order to establish the radio resource. The ‘Channel Assignment’ message contains information about a radio bearer resource. 
   At step S 14 , after receiving the ‘Channel Assignment’ message from the RRC  721  in the asynchronous radio network, the RRC  713  in the asynchronous mobile station transmits the channel assignment message through the primitive of ‘UE Side Initiated Connection Establishment Confirm’ provided by the DC-SAP, to the CC entity in the asynchronous mobile station. After receiving the ‘Channel Assignment’ message from the RRC  713  in the asynchronous mobile station, the CC entity in the asynchronous mobile station stores information from the message. This message can be substituted for a ‘Radio Bearer Assignment Setup’. 
   At step S 15 , after transmitting the ‘Channel Assignment’ message, the RRC  721  in the asynchronous radio network transmits a ‘Radio Bearer Assignment Setup’ message for substantially establishing the radio resource between the asynchronous radio network and the asynchronous mobile station, to the RRC  713  in the asynchronous mobile station. 
   At step S 16 , after receiving the ‘Radio Bearer Assignment Setup’ message from the RRC  721  in the asynchronous radio network, the RRC  713  in the asynchronous mobile station stores information necessary for establishing the radio resource, and transmits a ‘Radio Bearer Assignment Setup’ message containing the rest of information to the CC entity in the asynchronous mobile station, through the primitive of ‘UE Side Initiated Radio Access Bearer Establishment Indication’ provided by the DC-SAP. After that, it establishes the radio resource by using the stored information. 
   At step S 17 , after receiving the ‘Radio Bearer Assignment Setup’ message from the RRC  713  in the asynchronous mobile station, the CC entity in the asynchronous mobile station stores information extracted exacted from the ‘Radio Bearer Assignment Setup’ message, and transmits a ‘Radio Bearer Assignment Setup Complete’ message through the primitive of ‘UE Side Initiated Radio Access Bearer Establishment Response’ provided by the DC-SAP, to the RRC in the asynchronous mobile station. 
   At step S 18 , after receiving the ‘Radio Bearer Assignment Setup Complete’ message from the CC entity  711  in the asynchronous mobile station, the RRC  713  in the asynchronous mobile station completes establishment of the radio resource, and then transmits a ‘Radio Bearer Setup Complete’ message to the RRC  721  in the asynchronous radio network. 
   At step S 19 , after receiving the ‘Radio Bearer Setup Complete’ message from the RRC  713  in the asynchronous mobile station, the RRC  721  in the asynchronous radio network is informed that establishment of the radio resource is completed, and transmits a ‘Service Connect’ message through the ‘Downlink Direct Transfer’ message to the RRC  713  in the asynchronous mobile station. Thereby, structural information for service originally requested by the asynchronous mobile station is transmitted to the asynchronous mobile station, so that the asynchronous mobile station can perform call processing according to this structural information. 
   At step S 20 , after receiving the ‘Service Connect’ message from the RRC  721  in the asynchronous radio network, the RRC  713  in the asynchronous mobile station transmits the ‘Service Connect’ message through the primitive of the ‘Data Transfer Indication’ provided by the DC-SAP, to the CC entity  711  in the asynchronous mobile station. 
   At step S 21 , after receiving the ‘Service Connect’ message from the RRC  713  in the asynchronous mobile station, the CC entity in the asynchronous mobile station stores the structural information for service, and transmits a ‘Service Connect Complete’ message through the primitive of ‘Data Transfer Request’ provided by the DC-SAP to the RRC in the asynchronous mobile station. 
   At step S 22 , after receiving the ‘Service Connect Complete’ message from the CC entity  711  in the asynchronous mobile station, the RRC  713  in the asynchronous mobile station transmits the ‘Service Connect Complete’ message through the ‘Uplink Direct Transfer’ message, to the RRC  721  in the asynchronous radio network. 
   At step S 23 , after receiving the ‘Service Connect Complete’ message from the RRC  713  in the asynchronous mobile station, the RRC  721  in the asynchronous radio network is informed that establishment of the structural information for service is completed and the establishment of the radio resource is completed, and transmits an ‘Assignment Complete’ message to the synchronous core network, in order to inform the synchronous core network that the asynchronous mobile station is in a state of being capable of a phone call. 
   At step S 24 , after receiving the ‘Assignment Complete’ message from the asynchronous radio network, the synchronous core network is informed that the asynchronous mobile station is in the state of being capable of the phone call, and transmits a Ring Back Tone ordering to wait until a phone call gets started through an ‘Alert’ message, to the RRC  721  in the asynchronous radio network. 
   At step S 25 , after receiving the ‘Alert’ message from the CC entity in the synchronous core network, the asynchronous radio network transmits the ‘Alert’ message through the ‘Downlink Direct Transfer’ message to the RRC  713  in the asynchronous mobile station. 
   At step S 26 , after receiving the ‘Alert’ message from the RRC  721  in the asynchronous radio network, the RRC  713  in the asynchronous mobile station transmits this message through the primitive of the ‘Data Transfer Indication’ provided by the DC-SAP, to the CC entity  711  in the asynchronous mobile station. After receiving the ‘Alert’ message, the CC entity  711  in the asynchronous mobile station generates a tone for a user, interlocking with a hardware. 
   By proceeding with the steps described so far, interlocking between the asynchronous mobile station and the synchronous core network can be carried out. 
   Embodiment 2 
     FIG. 8  is a flow chart representing a second embodiment of a method for processing a call in the asynchronous mobile communication system. Particularly,  FIG. 8  represents a Call Clearing Flow initiated by the asynchronous mobile station, where the synchronous ANSI-41 core network is coupled to the asynchronous radio network in the asynchronous mobile communication system. 
   Reference numerals  710 ,  711 ,  712  and  713  denote an asynchronous mobile station, a call control (CC) entity, a Mobility Management (MM) and a radio resource controller (RRC), respectively. The asynchronous mobile station includes the call control (CC) entity  711 , the Mobility Management (MM)  712  and the radio resource controller (RRC)  713 . 
   Reference numerals  720  and  721  denote an asynchronous radio network UTRAN and a radio resource controller (RRC) included in the asynchronous radio network UTRAN  720 ,  1  respectively. 
   Reference numerals  730 ,  731  and  732  denote a synchronous ANSI-41 core network, a Mobility Management (MM) and a call control (CC) entity, respectively. And the Mobility Management (MM)  731  and the call control (CC) entity  732  are included in a Mobile Switching Center (MSC) of the synchronous core network  730 . 
   Hereinafter, a process for a call clearing in this interlocking structure will be described. 
   At step S 31 , when terminating the phone call, the CC entity  711  in the asynchronous mobile station transmits a ‘Release Order’ message requesting to release a wire resource and a radio resource through the primitive of the ‘Data Transfer Request’ provided by the DC-SAP to the RRC  713  in the asynchronous mobile station. 
   At step S 32 , after receiving this message, the RRC  713  in the asynchronous mobile station transmits the ‘Release Order’ message through the ‘Uplink Direct Transfer’ message to the RRC in the asynchronous radio network. 
   At step S 33 , after receiving the Direct Transfer RRC message, the asynchronous radio network is informed that the asynchronous mobile station requests to release the wire and radio resources, and transmits a ‘Clear Request’ message to the CC entity in the MSC of the synchronous core network. 
   At step S 34 , after receiving this message, the CC entity in the MSC of the synchronous core network is informed that the asynchronous mobile station requests to release the wire resource and the radio resource, and transmits a ‘Clear Command’ message to the asynchronous radio network, in order to command the asynchronous radio network to release the wire resource and the radio resource. 
   At step S 35 , after receiving this message, in response to the ‘Release Order’ message received from the asynchronous mobile station at the step S 32 , the asynchronous radio network transmits a ‘Release Order’ message to the RRC  713  in the asynchronous mobile station, in order to start to release the wire resource and the radio resource, and then starts to release the wire resource and the radio resource. 
   At step S 36 , after receiving this message, the RRC in the asynchronous mobile station transmits the ‘Release Order’ message through the primitive of the ‘Data Transfer Indication’ provided by the DC-SAP, to the CC entity in the asynchronous mobile station. 
   At step S 37 , in order to release the radio resource, the RRC  721  in the asynchronous radio network transmits a ‘Radio Bearer Release’ message to the RRC  713  in the asynchronous mobile station. 
   At step S 38 , after receiving this message, the RRC in the asynchronous mobile station performs releasing a radio resource for exclusive use, and transmits a ‘Radio Bearer Release’ message containing information of the release completion through the primitive of an ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by DC-SAP, to the CC entity in the asynchronous mobile station. 
   At step S 39 , after receiving this message, the CC entity in the asynchronous mobile station is informed that the radio resource for exclusive use between the asynchronous mobile station and the asynchronous radio network was released, and in response to the received message, transmits a ‘Radio Bearer Release Complete’ message through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the RRC  713  in the asynchronous mobile station  710 . 
   At step S 40 , after receiving the message, the RRC  713  in the asynchronous mobile station transmits a ‘Radio Bearer Release Complete’ message to the RRC in the asynchronous radio network. The message serves to inform that releasing the radio resource for exclusive use between the asynchronous mobile station and the asynchronous radio network is completed. 
   At step S 41 , after receiving the message, the RRC  721  in the asynchronous radio network mobile station transmits an ‘RRC Connection Release’ message to the RRC  713  in the asynchronous mobile station, in order to release a Layer-3 signaling and a radio resource. 
   At step S 42 , after receiving the ‘RRC Connection Release’ message, the RRC  713  in the asynchronous mobile station  710  is informed that the Layer-3 signaling and the radio resource should be released for should release between the asynchronous radio network and itself; transmits an ‘RRC Connection Release Complete’message to release the Layer-3 signaling and the radio resource to the RRC in the asynchronous radio network; and performs releasing the Layer-3 signaling and the radio resource. 
   At step S 43 , after receiving the ‘RRC Connection Release Complete’ message, the RRC in the asynchronous radio network is informed that the Layer-3 signaling and the radio resource for common use were released, and transmits a ‘Clear Complete’ message to the protocol entity in the synchronous core network, so that the CC protocol entity can be informed that the release of all resources and signaling is completed between the asynchronous mobile station and itself. 
   By proceeding with the steps described above, the connected call can be released. 
     FIG. 9  is a flow chart representing a method for processing a call clearing, where the synchronous core network initiates a call-clearing signal in the asynchronous mobile communication system. 
   Reference numerals  710 ,  711 ,  712  and  713  denote an asynchronous mobile station, a call control (CC) entity, a Mobility Management (MM) and a radio resource controller (RRC), respectively. The asynchronous mobile station  710  includes the call control (CC) entity, the Mobility Management (MM) and the radio resource controller (RRC). 
   Reference numerals  720  and  721  denote an asynchronous radio network UTRAN, and a radio resource controller (RRC) included in the asynchronous radio network UTRAN  720 , respectively. 
   Reference numerals  730 ,  731  and  732  denote a synchronous ANSI-41 core network, a Mobility Management (MM) and a call control (CC) entity, respectively. And the Mobility Management (MM)  731  and the call control (CC) entity  732  are included in the synchronous core network  730 . 
   At step S 51 , the synchronous core network transmits a ‘Clear Command’ message to the asynchronous radio network, in order to command the asynchronous radio network to release the wire resource and the radio resource. 
   At step S 52 , after receiving the ‘Clear Command’ message, the asynchronous radio network transmits a ‘Release Order’ message to the RRC  713  in the asynchronous mobile station  710  in order to start releasing the wire resource and the radio resource, and starts releasing the wire resource and the radio resource. 
   At step S 53 , after receiving the ‘Release Order’ message, the RRC  713  in the asynchronous mobile station  710  transmits the ‘Release Order’ message through the primitive of the ‘Data Transfer Indication’ provided by DC-SAP, to the CC entity in the asynchronous mobile station. 
   At step S 54 , the RRC in the asynchronous radio network transmits a ‘Radio Bearer Release’ message to the RRC in the asynchronous mobile station, in order to release the radio resource. 
   At step S 55 , after receiving the ‘Radio Bearer Release’ message, the RRC  713  in the asynchronous mobile station  710  performs releasing the radio resource for exclusive use, and transmits the ‘Radio Bearer Release’ message containing information of completing the release, through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the CC entity  711  in the asynchronous mobile station  710 . 
   At step S 56 , after receiving the ‘Radio Bearer Release’ message, the CC entity in the asynchronous mobile station is informed that the radio resource for exclusive use between the asynchronous mobile station  710  and the asynchronous radio network  720  was released, and in response to the received message, transmits the ‘Radio Bearer Release Complete’ message through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the RRC  713  in the asynchronous mobile station  710 . 
   At step S 57 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC  713  in the asynchronous mobile station  710  transmits the ‘Radio Bearer Release Complete’ message to the RRC  721  in the asynchronous radio network  720 , in order to inform that the release of the radio resource for exclusive use between the asynchronous radio network and itself was completed. 
   At step S 58 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC  721  in the asynchronous radio network  720  transmits the ‘RRC Connection Release’ message to the RRC  713  in the asynchronous mobile station  710 , in order to release the Layer-3 signaling and the radio resource. 
   At step S 59 , after receiving the ‘RRC Connection Release’ message, the RRC  713  in the asynchronous mobile station  710  is informed that the Layer-3 signaling and the radio resource should be released between the asynchronous radio network  720  and itself; transmits the ‘RRC Connection Release Complete’ message to release the Layer-3 signaling and the radio resource, to the RRC  721  in the asynchronous radio network  720 ; and performs releasing the Layer-3 signaling and the radio resource. 
   At step S 60 , after receiving the ‘RRC Connection Release Complete’ message, the RRC  721  in the asynchronous radio network  720  is informed that the Layer-3 signaling and the radio resource were released, and transmits a ‘Clear Complete’ message to the CC protocol entity in the synchronous core network, so that the CC protocol entity can be informed that the release of all resources and signaling is completed between the asynchronous mobile station  710  and itself. 
   Embodiment 3 
     FIGS. 10A and 10B  are flow charts representing a method for processing a handoff in the asynchronous mobile communication system in accordance with the present invention. In this system, a synchronous core network is interlocked with a source asynchronous radio network and a target asynchronous radio network. 
   Reference numerals  740 ,  741  and  742  denote an asynchronous mobile station, a synchronous call control (CC) entity, and an asynchronous resource controller (RRC) included in the asynchronous mobile station  740 , respectively. 
   Reference numerals  750  and  751  denote a source asynchronous radio network, and an asynchronous radio resource controller (RRC) included in the source asynchronous radio network, respectively. 
   Reference numerals  760 ,  761  and  762  denote a synchronous ANSI-41 core network, a synchronous radio resource (RR) included in the synchronous core network, and a synchronous call control (CC) entity included in the synchronous core network, respectively. 
   Reference numerals  770  and  771  denote a target asynchronous radio network interlocked with the synchronous core network  760 , and an asynchronous radio resource controller (RRC) included in the target asynchronous radio network  770 , respectively. 
   At step S 71 , the RRC in the source asynchronous radio network provides information capable of measuring performance and power of a radio link to the RRC in the asynchronous mobile station. With this information, the asynchronous mobile station measures the radio link, and transmits the result of measurement to the RRC in the source asynchronous radio network  750 , and then it is determined whether a handoff is possible or not, based on this result. In order to perform the above process, the RRC in the source asynchronous radio network transmits a ‘Measurement Control’ message to the RRC in the asynchronous mobile station  740 . 
   At step S 72 , after receiving the ‘Measurement Control’ message from the RRC in the source asynchronous radio network  750 , the asynchronous mobile station  740  measures the performance and the power of the radio link with information in the received message, and transmits a ‘Measurement Report’ message containing the result of the measurement to the RRC  751  in the source asynchronous radio network  750 . After receiving the ‘Measurement Report’ message, the RRC  751  in the asynchronous radio network  750  determines, with information in the received message, whether it allows a handoff. 
   At step S 73 , if the RRC  751  in the asynchronous radio network  750  determines to allow the handoff, the RRC  751  in the asynchronous radio network  750  transmits a ‘Handoff Required’ message for requesting a handoff, to the RR  761  in the MSC of the synchronous core network  760 . This message includes information of the target asynchronous radio network targeted for handoff. 
   At step S 74 , after receiving the ‘Handoff Required’ message from the source asynchronous radio network  750 , the RR  761  in the MSC of the synchronous core network  760  analyzes information in the received message, and grasps information of the target asynchronous radio network which is a target base station for the handoff. And then, by transmitting a ‘Handoff Request’ message to the target asynchronous radio network, the RR  761  in the synchronous core network  760  informs that the handoff to the target asynchronous radio network will be generated. 
   At step S 75 , after receiving the ‘Handoff Request’ message from the RR  761  in the synchronous core network net work  760 , the target asynchronous radio network  770  is informed that the handoff will be generated; analyzes and stores information of the source asynchronous radio network  750  and the asynchronous mobile station  740 , which are related to the handoff; and is prepared for the handoff. And then, in response to the received message, the target asynchronous radio network  770  transmits a ‘Handoff Request Ack’ message to the synchronous core network  760 . 
   At step S 76 , after receiving the ‘Handoff Request Ack’ message from the target asynchronous radio network, the RR  761  in the synchronous core network  760  is informed that the target asynchronous radio network was prepared for the handoff, and transmits a ‘Handoff Command’ message to the source asynchronous radio network  750 . 
   At step S 77 , after receiving the ‘Handoff Command’ message from the RR  761  in the synchronous core network  760 , the source asynchronous radio network  750  transmits information of the target asynchronous radio network which is a target base station for the handoff through a ‘Physical Channel Reconfiguration’ message to the RRC  742  in the asynchronous mobile station  740 . 
   At step S 78 , after receiving the ‘Physical Channel Reconfiguration’ message from the RRC in the source asynchronous radio network  750 , the RRC in the asynchronous mobile station  740  is prepared for the handoff to the target asynchronous radio network  770 . In response to the received message, the RRC  742  transmits a ‘MS Ack Order’ message to the RRC  751  in the source asynchronous radio network. 
   At step S 79 , after receiving the ‘MS Ack Order’ message, the RRC  751  in the source asynchronous radio network is informed that the asynchronous mobile station  740  commences the handoff, and transmits a ‘Handoff Commenced’ message to the RR  761  in the synchronous core network  760 . 
   At step S 80 , the establishment of the radio link and the synchronization are performed for communication between the asynchronous mobile station  740  and the target asynchronous radio network  770 . 
   At step S 81 , the RRC  742  in the asynchronous mobile station  740  transmits a ‘RRC Connection Re-establishment Request’ message to the target asynchronous radio network  770 , in order to establish a Layer-3 signaling and use a Dedicated Control Channel (DCCH) between the target asynchronous radio network  770  and itself. 
   At step S 82 , after receiving the ‘RRC Connection Re-establishment request’ message, the target asynchronous radio network  770  transmits a ‘RRC Connection Re-establishment’ message to the RRC  742  in the asynchronous mobile station  740 , in order to provide information of the Layer-3 signaling establishment and the DCCH to the asynchronous mobile station  740 . 
   At step S 83 , after receiving the ‘RRC Connection Re-establishment’ message, the RRC  742  in the asynchronous mobile station  740  analyzes information contained in the message and then establishes the Layer-3 signaling and the DCCH between the target asynchronous radio network  770  and itself, and transmits a ‘RRC Connection Re-establishment Complete’ message to the RRC  771  in the target asynchronous radio network  770  in order to inform that establishment is completed. 
   At step S 84 , after completing the establishment of the radio link, synchronization and the establishment of the signaling for radio protocol between the target asynchronous radio network  770  and itself, the RRC  742  in the asynchronous mobile station  740  transmits a ‘Physical Channel Reconfiguration’ message to the RRC  771  in the target asynchronous radio network  770 , in order to inform that handoff is completed. 
   At step S 85 , after receiving the ‘Physical Channel Reconfiguration’ message, the target asynchronous radio network  770  is informed that the handoff was completed, and transmits a ‘Handoff Complete’ message to the RR  761  in the synchronous core network in order to inform that the target asynchronous radio network  770  is communicating presently with the asynchronous mobile station. 
   At step S 86 , after receiving the ‘Handoff Complete’ message, the RR in the synchronous core network  760  informs the CC entity  762  that the handoff was completed, through an internal communication. After being informed, the CC entity  762  in the synchronous core network  760  transmits a ‘Clear Command’ message to the source asynchronous radio network  750  in order to release a radio resource and a wire resource of the source asynchronous radio network  750 . 
   At step S 87 , after receiving the ‘Clear Command’ message, the RRC in the source asynchronous radio network is informed that the radio and the wire resource should be released, and transmits a ‘Radio Bearer Release’ message to the RRC  742  in the asynchronous mobile station  740  in order to release the radio resource. 
   At step S 88 , after receiving the ‘Radio Bearer Release’ message, the RRC  742  in the asynchronous mobile station  740  performs releasing the radio resource for exclusive use, and transmits the ‘Radio Bearer Release’ message containing information of completing the release, through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the CC entity  741  in the asynchronous mobile station  740 . 
   At step S 89 , after receiving the ‘Radio Bearer Release’ message, the CC entity  741  in the asynchronous mobile station  740  is informed that the radio resource for exclusive use between the asynchronous mobile station  740  and the asynchronous radio network  750  was released, and in response to the received message, transmits the ‘Radio Bearer Release Complete’ message through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the RRC  742  in the asynchronous mobile station  740 . 
   At step S 90 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC  742  in the asynchronous mobile station  740  transmits the ‘Radio Bearer Release Complete’ message to the RRC  751  in the asynchronous radio network  750 , in order to inform that the release of the radio resource for exclusive use between the asynchronous radio network and itself was completed. 
   At step S 91 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC  751  in the asynchronous radio network  750  transmits the ‘RRC Connection Release’ message to the RRC  742  in the asynchronous mobile station, in order to release the Layer-3 signaling and the radio resource. 
   At step S 92 , after receiving the ‘RRC Connection Release’ message, the RRC  742  in the asynchronous mobile station  740  is informed that the Layer-3 signaling and the radio resource should be released between the asynchronous radio network  750  and itself; transmits the ‘RRC Connection Release Complete’ message to release the Layer-3 signaling and the radio resource, to the RRC  751  in the asynchronous radio network  750 ; and performs releasing the Layer-3 signaling and the radio resource. 
   At step S 93 , after receiving the ‘Radio Connection Release Complete’ message, the RRC  751  in the asynchronous radio network  750  is informed that the Layer-3 signaling and the radio resource for common use were released, and transmits a ‘Clear Complete’ message to the CC entity  762  in the synchronous core network  760 , so that the CC entity can be informed that releasing of all resources and signaling is completed between the asynchronous mobile station  740  and itself. 
     FIGS. 11A and 11B  are flow charts representing a method for processing a handoff in the asynchronous mobile communication system in accordance with the present invention. Particularly, in this system, a synchronous core network is interlocked with a source asynchronous radio network and a target synchronous radio network. 
   Reference numerals  740 ,  741 ,  742  and  743  denote an asynchronous mobile station, a synchronous call control (CC) entity, an asynchronous radio resource controller (RRC) included in the asynchronous mobile station, and a synchronous radio resource (RR), respectively. 
   Reference numerals  750  and  751  denote a source asynchronous radio network, and an asynchronous radio resource controller (RRC) included in the source asynchronous radio network, respectively. 
   Reference numerals  760 ,  761  and  762  denote a synchronous ANSI-41 core network, a synchronous radio resource (RR) included in the synchronous core network, and a synchronous call control (CC) entity included in the synchronous core network, respectively. 
   Reference numeral  780  denotes a target synchronous radio network interlocked with the synchronous core network  760 . 
   At step S 101 , the RRC  751  in the source asynchronous radio network provides information necessary for measuring performance and power of a radio link to the RRC  742  in the asynchronous mobile station  740 . The asynchronous mobile station  740  measures the performance and the power of the radio link based on the information which is received from the source asynchronous radio network  750 . Thus, for the step S 101 , the RRC in the asynchronous radio network transmits a ‘Measurement Control’ message to the RRC in the asynchronous mobile station. 
   At step S 102 , after receiving the ‘Measurement Control’ message, the asynchronous mobile station measures the performance and the power of the radio link based on the information contained in the received message, and transmits the result of measurement through a ‘Measurement Report’ message to the RRC  751  in the source asynchronous radio network  750 . After receiving the ‘Measurement Report’ message, the RRC  751  in the source asynchronous radio network  750  determines, based on the information contained in the received message, whether a handoff is allowed. 
   If the handoff is allowed, at step S 103 , the source asynchronous radio network  750  transmits a ‘Handoff Required’ message for requesting a handoff to the RR  761  in the MSC of the synchronous core network. The ‘Handoff Required’ message includes information of a target MC system which is a target base station for the handoff. 
   At step S 104 , after receiving the ‘Handoff Required’ message from the RRC  751  in the source asynchronous radio network  750 , the RR  761  in the synchronous core network  760  analyzes information contained in the received message, and grasps information of the target MC system which is a target base station for the handoff. Then, the RR  761  in the synchronous core network  760  transmits a ‘Handoff Request’ message to the target MC system, in order to inform that the handoff to the target MC system will be generated. In response to the ‘Handoff Request’ message, the target MC system determines whether it stores a resource to be assigned to the mobile station that requires the handoff. 
   At step S 105 , in case the target MC system stores the resource to be assigned, it assigns the proper resource and connects to a call of the mobile station that requires the handoff. The target MC system transmits a Null Forward Traffic Channel Frame to the mobile station that requires the handoff. 
   At step S 106 , the target MC system transmits a ‘Handoff Request Ack’ message to the RR  761  in the synchronous core network  760 . 
   At step S 107 , after receiving the ‘Handoff Request Ack’ message, the RR  761  in the synchronous core network  760  is informed that the target MC system was prepared for the handoff, and transmits a ‘Handoff Command’ message to the RRC  751  in the source asynchronous radio network  750 . 
   At step S 108 , after receiving the ‘Handoff Command’ message, the RRC in the source asynchronous radio network transmits information of the target MC system which is a target base station for the handoff through an ‘Inter System Handover Command’ message to the RRC  742  in the asynchronous mobile station  740 . 
   At step S 109 , after receiving the ‘Inter System Handover Command’ message, the RRC  742  in the asynchronous mobile station  740  gets prepared for the handoff to the target MC system, and, in response to the received message, transmits a ‘MS Ack Order’ message to the RRC in the source asynchronous radio network. 
   At step S 110 , after receiving the ‘MS Ack Order’ message, the RRC  751  in the source asynchronous radio network  750  is informed that the asynchronous mobile station commenced the handoff, and transmits a ‘Handoff Commenced’ message to the RR  761  in the synchronous core network  760  in order to inform that the handoff was commenced. 
   At step S 111 , by transmitting a Reverse Traffic Channel Frame and a Traffic Channel Preamble to the target MC system, the asynchronous mobile station performs an establishment of the radio link and a synchronization for a communication between the target MC system and itself. 
   At step S 112 , after completing the establishment of the radio link, the synchronization and the establishment of Signaling for the radio protocol, the asynchronous mobile station  740  transmits a ‘Handoff Completion Message’ message to the target MC system in order to inform that the handoff was competed. 
   At step S 113 , after receiving the ‘Handoff Completion Message’ message, the target MC system, in response to the received message, transmits a ‘BS Ack Order’ message to the asynchronous mobile station  740 . 
   At step S 114 , the target MC system is informed that the handoff was completed, transmits a ‘Handoff Completed’ message to the RR  761  in the synchronous core network  760  in order to inform that it is communicating with the present mobile station. 
   At step S 115 , after receiving the ‘Handoff Complete’ message, the RR  761  in the synchronous core network informs the CC entity in the MSC, through the internal communication, that the handoff was completed. After being informed, the CC entity in the synchronous core network transmits a ‘Clear Command’ message to the RRC  751  in the source asynchronous radio network  750  in order to release the radio resource and the wire resource between the source asynchronous radio network  750  and itself. 
   At step S 116 , after receiving the ‘Clear Command’ message, the RRC  751  in the source asynchronous radio network  750  is informed that the radio resource and the wire resource should be released, and transmits a ‘Radio Bearer Release’ message to the RRC  742  in the asynchronous mobile station  740  in order to release the radio resource. 
   At step S 117 , after receiving the ‘Radio Bearer Release’ message, the RRC in the asynchronous mobile station performs releasing the radio resource for exclusive use, and transmits the ‘Radio Bearer Release’ message containing information of completing the release, through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the CC entity  741  in the asynchronous mobile station  740 . 
   At step S 118 , after receiving the ‘Radio Bearer Release’ message, the CC entity in the asynchronous mobile station is informed that the radio resource for exclusive use between the asynchronous mobile station and the source asynchronous radio—network was released, and in response to the received message, transmits the ‘Radio Bearer Release Complete’ message through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the RRC  742  in the asynchronous mobile station  740 . 
   At step S 119 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC  742  in the asynchronous mobile station  740  transmits the ‘Radio Bearer Release Complete’ message to the RRC  751  in the source asynchronous radio network  750 , in order to inform that releasing the radio resource for exclusive use between the source asynchronous radio network  750  and itself was completed. 
   At step S 120 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC  751  in the source asynchronous radio network  750  transmits the ‘RRC Connection Release’ message to the RRC  742  in the asynchronous mobile station  740 , in order to release the Layer-3 signaling and the radio resource. 
   At step S 121 , after receiving the ‘RRC Connection Release’ message, the RRC  742  in the asynchronous mobile station  740  is informed that the Layer-3 signaling and the radio resource should be released between the source asynchronous radio network  750  and itself; transmits the ‘RRC Connection Release Complete’ message to release the Layer-3 signaling and the radio resource, to the RRC  751  in the source asynchronous radio network  750 ; and performs releasing the Layer-3 signaling and the radio resource. 
   At step S 122 , after receiving the ‘RRC Connection Release Complete’ message, the RRC  751  in the source asynchronous radio network  750  is informed that the Layer-3 signaling and the radio resource were released, and transmits a ‘Clear Complete’ message to the CC entity  762  in the synchronous core network, so that the CC entity can be informed that releasing of all resources and signaling is completed between the asynchronous mobile station  740  and itself. 
     FIGS. 12A and 12B  are flow charts representing a method for processing a handoff in the asynchronous mobile communication system. Particularly, in this system, a synchronous core network is interlocked with a source synchronous radio network and a target asynchronous radio network. 
   Reference numerals  810 ,  811 ,  812  and  813  denote a synchronous mobile station, a synchronous call control (CC) entity, an asynchronous radio resource controller (RRC) included in the synchronous mobile station  810  and a synchronous radio resource (RR), respectively. 
   A reference numeral  800  denotes a synchronous radio network. 
   Reference numerals  760 ,  761  and  762  denote a synchronous ANSI-41 core network, a synchronous radio resource (RR) included in the synchronous core network  760 , and a synchronous call control (CC) entity included in the synchronous core network  760 , respectively. 
   Reference numerals  790  and  791  denote a target asynchronous radio network, and an asynchronous radio resource controller (RRC) included in the asynchronous radio network  790 , respectively. 
   At step S 131 , a source MC system  800  transmits a ‘Candidate Frequency Search Request’ message requesting to measure a neighboring radio link to the RR  813  in the synchronous mobile station  810 . The neighboring radio link represents a radio link that is not used presently, but can be used for the handoff. 
   At step S 132 , after receiving the ‘Candidate Frequency Search Request’ message, the RR  813  in the synchronous mobile station  810  is informed that the neighboring radio link should be measured, and in response to the received message, transmits a ‘Candidate Frequency Search Response’ message to the source MC system  800 . 
   At step S 133 , after receiving the ‘Candidate Frequency Search Response’ message, the source MC system  800  transmits information about the neighboring radio link and information related to the measurement including a measurement scope and a measurement cycle, through a ‘Candidate Frequency Control’ message, to the RR  813  in the synchronous mobile station  810 . The mobile station is required to measure the above information. 
   At step S 134 , after receiving the ‘Candidate Frequency Control’ message, the RR  813  in the synchronous mobile station  810  stores information contained in the received message, and after measuring information about the neighboring radio link according to the stored information, transmits the result of measurement through a ‘Candidate Frequency Search Report’ message to the source MC system  800 . The source MC system  800 , based on the result contained in the received message, determines whether the handoff is allowed. 
   If the handoff is allowed, at step S 135 , the source MC system  800  transmits a ‘Handoff Required’ message requesting the handoff, to the RR  761  in the synchronous core network  760 . The ‘Handoff Required’ message contains information of the target DS RNC. The target DS RNC means the target asynchronous radio network. 
   At step S 136 , after receiving the ‘Handoff Required’ message, the RR  761  in the synchronous core network is informed that the source MC system  800  requests a handoff, and analyzes and grasps information contained in the received message. Then, the RR  761  transmits a ‘Handoff Request’ message to the target DS RNC  790 , in order to inform that the handoff to the target DS RNC will be generated. 
   After receiving the ‘Handoff Request’ message, the target DS RNC  790  is informed that the handoff will be generated; analyzes and stores information about the mobile station and the source MC system wherein the handoff will be generated; and determines whether it stores a resource to be assigned to the mobile station where the handoff will be generated. 
   If the target DS RNC  790  does store the resource to be assigned to the mobile station  810 , at step S 137 , it transmits a ‘Handoff Request Ack’ message to the RR  761  in the synchronous core network, in response to the received ‘Handoff Request’ message. 
   At step S 138 , after receiving the ‘Handoff Request Ack’ message, the RR  761  in the synchronous core network  800  is informed that the target DS RNC  790  was prepared for the handoff, and transmits a ‘Handoff Command’ message requesting the handoff to the source MC system  800 . 
   At step S 139 , after receiving the ‘Handoff Command’ message, the source MC system  800  transmits an Extended Handoff Direction Message or a General Handoff Direction Message requesting the handoff, to the RR  813  in the mobile station  810 . 
   At step S 140 , after receiving the Extended Handoff Direction Message or the General Handoff Direction Message, the RR  813  in the mobile station  810  gets prepared for the handoff to the target DS RNC  790 , and in response to the received message, transmits a ‘MS Ack Order’ message to the source MC system  800 . 
   At step S 141 , after receiving the ‘MS Ack Order’ message, the source MC system  800  is informed that the mobile station  810  commenced the handoff, and transmits a ‘Handoff Commenced’ message to the RR  761  in the synchronous core network  760  in order to inform that the handoff was commenced. 
   At step S 142 , an establishment of the radio link and a synchronization are performed for communication between the mobile station  810  and the target DS RNC  790 . 
   At step S 143 , the RRC  812  in the mobile station  810  transmits a ‘RRC Connection Re-establishment Request’ message to the target DS RNC, in order to establish a Layer-3 signaling and use a Dedicated Control Channel (DCCH) between the target DS RNC  790  and itself. 
   At step S 144 , after receiving the ‘RRC Connection Re-establishment Request’ message, the target DS RNC transmits a ‘RRC Connection Re-establishment’ message to the RRC in the mobile station  810 , in order to provide information of the Layer-3 signaling establishment and the DCCH to the mobile station  810 . 
   At step S 145 , after receiving the ‘RRC Connection Re-establishment’ message, the RRC  812  in the mobile station  810  analyzes information contained in the received message and then establishes the Layer-3 signaling and the DCCH between the target DS RNC  790  and itself, and transmits a ‘RRC Connection Re-establishment Complete’ message to the RRC  791  in the target DS RNC  790  in order to inform that the establishment is completed. 
   At step S 146 , after completing the establishment of the radio link, the synchronization and the establishment of the signaling for the radio protocol between the target DS RNC  790  and itself, the RRC  812  in the mobile station  810  transmits a ‘Intersystem Handover Complete’ message to the RRC  791  in the target DS RNC  790 , in order to inform that the handoff is completed. 
   At step S 147 , after receiving the ‘Intersystem Handover Complete’ message, the target DS RNC  790  is informed that the handoff was completed, and transmits a ‘Handoff Complete’ message to the RR  761  in the synchronous core network  760  in order to inform that it is communicating presently with the mobile station. 
   At step S 148 , after receiving the ‘Handoff Complete’ message, the RR  761  in the synchronous core network  760  informs the CC entity  762  in the synchronous core network  760  that the handoff was completed, through an internal communication. After being informed, the CC entity in the synchronous core network  760  transmits a ‘Clear Command’ message to the source MC system  800  in order to release a radio resource and a wire resource of the source MC system  800 . 
   At step S 149 , after receiving the ‘Clear Command’ message, the source MC system  800  releases all resources and the signaling that were established between the mobile station  810  and itself. 
   At step S 150 , after releasing all resources and signaling, the source MC system  800  transmits a ‘Clear Complete’ message to the CC entity  762  in the synchronous core network  760  in order to inform that all sources and signaling were released between the mobile station  810  and itself. 
     FIGS. 13A and 13B  are flow charts representing a method for processing a handoff in the asynchronous mobile communication system in accordance with the present invention. Particularly, in this system, a synchronous core network is interlocked with a source asynchronous radio network and an analog radio network. 
   Reference numerals  810 ,  811  and  812  denote a synchronous mobile station, a synchronous call control (CC) entity, and an asynchronous radio resource controller (RRC) included in the synchronous mobile station, respectively. 
   Reference numerals  820  and  821  denote an asynchronous radio network of asynchronous communication mode, and a RRC included in the asynchronous radio network, respectively. 
   Reference numerals  760 ,  761  and  762  denote a synchronous ANSI-41 core network, a synchronous radio resource (RR) included in the synchronous core network, and a synchronous call control (CC) entity included in the synchronous core network, respectively. 
   A reference numeral  830  denotes an analog radio network. 
   At step S 161 , the RRC  821  in the source DS RNC  820  provides information for measuring performance and power of a radio link to the RRC  812  in the mobile station  810 . The source DS RNC means the source asynchronous radio network. The mobile station  810  measures the radio link based on this information. Thus, the RRC in the source DS RNC  820  transmits a ‘Measurement Control’ message to the RRC  812  in the mobile station  810 . 
   At step S 162 , after receiving the ‘Measurement Control’ message, the mobile station measures performance and power of the radio link based on information contained in the received message, and transmits the result of the measurement through a ‘Measurement Report’ message to the RRC  821  in the source DS RNC  820 . After receiving the ‘Measurement Report’ message, the RRC in the source DS RNC determines, based on the information contained in the received message, whether a handoff is allowed. 
   If the handoff is allowed, at step S 163 , the source DS RNC  820  transmits a ‘Handoff Required’ message for requesting a handoff to the RR  761  in the synchronous core network. The ‘Handoff Required’ message includes information of a target analog system which is a target base station for the handoff. 
   At step S 164 , after receiving the ‘Handoff Required’ message, the RR  761  in the synchronous core network  760  analyzes information contained in the received message, and grasps information of the target analog system for the handoff. Then, the RR  761  in the synchronous core network  760  transmits a ‘Handoff Request’ message to the target analog system, in order to inform that the handoff to the target analog system will be generated. 
   After receiving the ‘Handoff Request’ message, the target analog system  830  is informed that the handoff will be generated; analyzes and stores information about the mobile station  810  and the source DS RNC  820  wherein handoff will be generated; and determines whether it stores a resource to be assigned to the mobile station where handoff will be generated. 
   In cases where the target analog system stores the resource to be assigned to the mobile station  810 , at step S 165 , it transmits a ‘Handoff Request Ack’ message to the RR  761  in the synchronous core network  760 , in response to the received ‘Handoff Request’ message. 
   At step S 166 , after receiving the ‘Handoff Request Ack’ message, the RR  761  in the synchronous core network  760  is informed that the target analog system was prepared for the handoff, and transmits a ‘Handoff Command’ message requesting handoff to the source DS RNC  820 . 
   At step S 167 , after receiving the ‘Handoff Command’ message, the source DS RNC transmits information of the target analog system for the handoff through an ‘Inter System Handover Command’ message to the RRC  812  in the mobile station  810 . 
   At step S 168 , after receiving the ‘Inter System Handover Command’ message, the RRC  812  in the mobile station  810  gets prepared for the handoff to the target analog system, and, in response to the received message, transmits an ‘MS Ack Order’ message to the RRC  821  in the source DS RNC  820 . 
   At step S 169 , after receiving the ‘MS Order’ message, the RRC  821  in the source DS RNC  820  is informed that the mobile station  810  commenced the handoff, and transmits a ‘Handoff Commenced’ message to the RR  761  in the synchronous core network  760  in order to inform that the handoff was commenced. 
   At step S 170 , the radio link is established, a vocoder is initialized, and a mutual signaling is exchanged for a communication between the mobile station  810  and the target analog system  830 . 
   At step S 171 , after the process at the step S 170  was completed, the target analog system  830  is informed that the handoff was completed, transmits a ‘Handoff Complete’ message to the RR  761  in the synchronous core network  760  in order to inform that it is communicating with the mobile station. 
   At step S 172 , after receiving the ‘Handoff Complete’message, the RR  761  in the synchronous core network  760  informs the CC entity  762 , through internal communication, that the handoff was completed. After being informed, the CC entity in the synchronous core network  760  transmits a ‘Clear Command’ message to the source DS RNC  820  in order to release the radio resource and the wire resource between the source DS RNC  820  and itself. 
   At step S 173 , after receiving the ‘Clear Command’ message, the RRC  821  in the source DS RNC  820  is informed that the radio resource and the wire resource should be released, and transmits a ‘Radio Bearer Release’ message to the RRC  812  of the mobile station in order to release the radio resource. 
   At step S 174 , after receiving the ‘Radio Bearer Release’ message, the RRC in the mobile station  810  performs releasing the radio resource for exclusive use, and transmits the ‘Radio Bearer Release’ message containing information of completing the release, through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the CC entity  811  in the mobile station  810 . 
   At step S 175 , after receiving the ‘Radio Bearer Release’ message, the CC entity  811  in the mobile station  810  is  1 — 15  informed that the radio resource for exclusive use between the mobile station  810  and the source DS RNC  820  was released, and in response to the received message, transmits the ‘Radio Bearer Release Complete’ message through the primitive of the ‘IF Side Initiated Radio Access Bearer Release Indication’ provided by the DC-SAP, to the RRC  812  in the mobile station  810 . 
   At step S 176 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC in the mobile station transmits the ‘Radio Bearer Release Complete’ message to the RRC  821  in the source DS RNC  820 , in order to inform that releasing the radio resource for exclusive use between the source DS RNC  820  and itself was completed. 
   At step S 177 , after receiving the ‘Radio Bearer Release Complete’ message, the RRC in the source DS RNC  820  transmits the ‘RRC Connection Release’ message to the RRC in the mobile station  810 , in order to release the Layer-3 signaling and the radio resource for common use. 
   At step S 178 , after receiving the ‘RRC Connection Release’ message, the RRC in the mobile station  810  is informed that the Layer-3 signaling and the radio resource for common use should be released between the source DS RNC  820  and it; transmits the ‘RRC Connection Release Complete’ message to release the Layer-3 signaling and the radio resource for common use, to the RRC  821  in the source DS RNC  820 ; and performs releasing the Layer-3 signaling and the radio resource for common use. 
   At step S 179 , after receiving the ‘RRC Connection Release Complete’ message, the source DS RNC is informed that the Layer-3 signaling and the radio resource for common use were released, and transmits a ‘Clear Complete’ message to the CC entity  762  in the synchronous core network  760 , so that the CC entity  762  can be informed that releasing of all resources and signaling is completed between the mobile station  810  and it. 
   As can be seen from above, by performing the embodiments in accordance with the present invention, there are provided benefits that it is possible to process a call and a handoff well, even if a core network is connected to any one of a GSM-MAP network and an ANSI-41 network; and it is possible for a subscriber to an asynchronous mobile communication system to have a phone call with a subscriber to a synchronous ANSI-41 network or the other networks. 
   Although the preferred embodiments of the invention have been disclosed for illustrative purpose, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible, without departing from the scope and sprit of the invention as disclosed in the accompanying claims.