Abstract:
A method which can allow subscribers to select an international telephone service provider and appropriately provide a wireless communication service to a mobile station subscribed to a foreign wireless communication system is disclosed. The method includes the steps of: a) storing information as to whether the international roaming mobile station subscribes to an international roaming service in a subscriber profile of the mobile station; b) storing MSC IDs in a database of HLR; c) determining whether a REGNOT message is from an MSC of a home system based on the MSC IDs stored in the database when the REGNOT message is inputted from the MSC to the HLR; and d) sending information as to whether the international roaming mobile station subscribes to the international roaming service to the MSC based on the subscriber information when the RENOT message is not from the home system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority to Korean patent application No. 99-57715, filed Dec. 15, 1999.  
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a method of providing a wireless communication service to an international roaming mobile station, more particularly to a method which can allow subscribers to select an international telephone service provider and appropriately provide a wireless communication service to a mobile station subscribed to a foreign wireless communication system.  
           [0004]    2. Prior Art  
           [0005]    The operation of a cellular telephone network for delivering inputted calls to dialed cellular mobile stations is well known in the art. When a mobile station is dialed and a call origination is sent to a home MSC (Mobile Switching Center), in response to the call origination, the home MSC sends a location query message to the HLR (Home Location Resistor). The HLR confirms which MSC serves at the area visited by the dialed mobile station. For preparing call delivery, a routing request message is forwarded from the HLR to the visited MSC. The visited MSC determines the location of the called (or dialed) mobile station and assigns an appropriate routing number (for example, a temporary local directory number) to the called mobile station. And then, the visited MSC responds to the routing request message of the HLR with the routing number. The routing number is forwarded to the home MSC to be used for establishing a communication link between the home MSC and the visited MSC. On the other hand, the delivery of the call to the called mobile station is accomplished by establishing a communication link with a base station controller connected with a base station currently servicing the called mobile station. And then, the radio frequency communication link between the base station and the called mobile station is established.  
           [0006]    However, when a calling party number according to a foreign telephone number plan is used as the “Calling Party Number” parameter value of a call setup message, a problem can occur that a communication link for an international roaming mobile station can not be established because of the difference between the foreign and domestic telephone number plans. Furthermore, when a mobile station subscribed to a wireless telephone network of one country is internationally roaming, it is impossible for the subscriber of the mobile station to select a variety of services provided from the subscribed wireless telephone network as desired, as well as to receive an international call service through his desirable international telephone service provider.  
         SUMMARY OF THE INVENTION  
         [0007]    Therefore, the present invention has been made by taking the above facts into consideration, and an object of the present invention is to provide a method which allows a domestic subscriber to selectively receive an international roaming service.  
           [0008]    It is another object of the present invention to provide a method which allows each of the subscribers to select an international telephone service provider when the subscribers receive the international roaming service.  
           [0009]    It is a further object of the present invention to provide a method which can provide a wireless communication service to a visiting mobile station international roaming.  
           [0010]    In order to achieve the above objects, a method according to one aspect of the present invention includes the steps of: a) storing information as to whether the internationally roaming mobile station subscribes to an international roaming service in a subscriber profile of the mobile station; b) storing mobile switching center identifications (MSC IDs) in a database of a home location register(HLR); c) determining whether a registration notification (REGNOT ) message is from an MSC of a home system based on the MSC IDs stored in the database when the REGNOT message is inputted from the MSC to the HLR; and d) sending information as to whether the international roaming mobile station subscribes to the international roaming service to the MSC based on the subscriber information when the RENOT message is not from the home system.  
           [0011]    A method according to another aspect of the present invention includes the steps of: a) registering the international roaming mobile station at an MSC; b) determining whether a routing request message for the international roaming mobile station is for an international call when the routing request message is received at the MSC; and c) generating an international routing number of the international roaming mobile station when the routing request message is for an international call and sending the international routing number.  
           [0012]    According to the present invention, a method and an apparatus for repeating a forward link communication signal are provided, which can allow the subscribers to select one international telephone service provider and allow international roaming mobile stations to receive a wireless communication service regardless of the telephone number scheme differences between the countries.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    This invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings, in which:  
         [0014]    [0014]FIG. 1 is a view showing one example of international wireless communication network;  
         [0015]    [0015]FIG. 2 is a signal flow and network operation diagram illustrating the registration of an international roaming mobile station according to the present invention;  
         [0016]    [0016]FIG. 3 is a signaling flow and network operation diagram illustrating the calling operation of the international roaming mobile station  161  registered in the second country wireless communication network  32  according to the present invention; and  
         [0017]    [0017]FIG. 4 is a signaling flow and network operation diagram illustrating the process of providing the call service to a mobile station subscribed in the second country wireless communication network according to the present invention when the mobile station visits the first country wireless communication network  12 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    Preferred embodiments of the present invention will be illustrated below with reference to the accompanying drawings.  
         [0019]    [0019]FIG. 1 is a view showing one example of international wireless communication network.  
         [0020]    Referring to FIG. 1, an international wireless communication network  10  includes the first country wireless communication network  12  and the second country wireless communication network  32 . In FIG. 1, while the wireless communication networks for the two countries are only depicted, it is understood in the art that the international wireless communication network  10  includes the plurality of country wireless communication networks which are interconnected with one another. Also, assuming that the present invention is embodied in the first country wireless communication network  12 , the present invention will be described in detail. Therefore, it is understood in the art that the present invention is not limited to a particular wireless communication network.  
         [0021]    The first country wireless communication network  12  includes the plurality of interconnected MSCs (mobile switching centers)  14 . Though only three MSCs  14  are depicted in the FIG. 1, it can be understood in the art that the first country wireless communication network  12  may include more than three interconnected MSCs.  
         [0022]    The MSCs  14  provide digital or analog mobile telephone (for example, cellular, PCS, etc.) service to the plurality of subscriber mobile stations  16 . The MSCs  14  are interconnected for communication with one another through both signaling links  20  (illustrated with broken lines) and voice trunks  18  (illustrated with solid lines). The voice trunks  18  provide voice and data communications paths used to carry subscriber communications between the MSCs  14 . The signaling links  20  carry command signals between the MSCs  14  used for setting up and releasing voice and data communications links over the voice trunks  18 , and for controlling the provision of service features to the subscriber mobile stations  16 . The MSCs  14  are connected to an HLR (home location register)  22  by means of the signaling links  20 .  
         [0023]    The HLR  22  has a database (not shown) which stores information concerning the assigned subscriber mobile stations  16  comprising location information and service information. Further, according to the present invention, the database of the HLR  22  stores information as to whether each of the mobile stations  16  subscribes to an international roaming service and if subscribed, which of the international telephone service providers each of subscribers is served with the international roaming service through, such as international telephone service numbers. The HLR  22  stores ID of each MSC of the second country wireless communication network  32  and MSC IDs of other country wireless communication network (not shown). There are the plurality of virtual origination numbers stored at the HLR  22  for subscribers of the second and any other countries wireless communication networks. When requested from the MSCs  14 , the HLR  22  assigns the plurality of virtual origination numbers to the MSCs  14 , respectively.  
         [0024]    Also, the MSCs  14  are linked to the VLR  26 . The VLR  26  dynamically stores subscriber information for subscriber mobile stations currently served by the MSCs  14 .  
         [0025]    The second country wireless communication network  32  includes the plurality of MSCs  34  interconnected with one another. In FIG. 1, though only three MSCs  34  are depicted, it is understood in the art that the second country wireless communication network  32  may include more than three MSCs  34 . The MSCs  34  conventionally provide the plurality of subscriber mobile stations  36  with a digital or analog wireless communication service. For example, the MSCs  34  operate based on the standard IS-41. The MSCs  34  are interconnected for communication with one another via signaling links  40  and voice trunks  38 . As mentioned above, the voice trunks  38  provide voice and data communications paths used to carry subscriber communications between the MSCs  34 . The signaling links  40  carry command signals between the MSCs  34  used for setting up and releasing voice and data communications links over the voice trunks  38 , and for controlling the provision of service features to the subscriber mobile stations  36 . The MSCs  34  are connected to an HLR  42  by means of the signaling links  44 . The MSCs  34  are connected to an HLR  42  by means of the signaling links  20 .  
         [0026]    The HLR  42  has a database (not shown) which stores information concerning the assigned subscriber mobile stations  36  comprising location information and service information. The HLR  42  operates based on the standard IS- 41 . Further, the MSCs  34  are linked to the VLR  46 . The VLR  46  dynamically stores subscriber information for subscriber mobile stations currently served by the MSCs  34 .  
         [0027]    An international gateway (IGW)  50  is used to connect at least one of the MSCs  14  of the first country wireless communication network  12  with at least one of the MSCs  34  of the second country wireless communication network  32 . It is understood in the art that the IGW  50  can be used to connect a variety of networks for example, PSTN, international telephone service providers, satellite communication networks, etc., with one another.  
         [0028]    In FIG. 1, when the mobile station  16  subscribed to the first country wireless communication network  12  visits at the second country wireless communication network  32 , the mobile station  16  must register in the MSC  34  of the second country wireless communication network  32  serving the area where the mobile station  16  visits.  
         [0029]    [0029]FIG. 2 is a signal flow and network operation diagram illustrating the registration of an international roaming mobile station according to the present invention.  
         [0030]    Referring to FIG. 2, when the mobile station subscribed to the first country wireless communication network  12  visits the service area of the MSC  34  of the second country wireless communication network  32 , the mobile station  161  sends a registration request message  200  to the MSC  34 . When the MSC  34  receives the registration request message  200 , the MSC  34  of the second country wireless communication network  32  sends a REGistration NOTification (REGNOT) message  210  through the IGW  50  to the HLR  22  of the first country wireless communication network to which the mobile station  161  is subscribed. When the HLR  22  receives the REGNOT message  210  from the MSC  34 , the HLR  22  determines which MSCs  34  generates the REGNOT message  210  based on the MSC ID stored in the database thereof. As the determination result, when the REGNOT message  210  is from a foreign MSC  34 , that is, an MSC  34  of the second country wireless communication network  32 , the HLR  22  retrieves the profile of the mobile station  161  from the database to determine whether the mobile station  161  is subscribed to the international roaming service( 220 ). And then, when the mobile station  161  is subscribed to the international roaming service, the HLR  22  stores the current location of the mobile station  161  in the database thereof and returns a REGNOT response message together with information (user&#39;s profile, interchange carrier ID, shared secret key for authentication, etc.) which the MSC  34  needs for communication service, that is, normal information to the MSC  34 . To the contrary, when the mobile station  161  does not subscribe to the international roaming service, the HLR  22  sends a REGNOT response message representing an authority denied parameter to the MSC  34  to prevent the MSC  34  from registering the mobile station  161 .  
         [0031]    The calling operation of the mobile station  161  registered in a foreign country network will be illustrated below with reference to FIG. 3.  
         [0032]    [0032]FIG. 3 is a signaling flow and network operation diagram illustrating the calling operation of the international roaming mobile station  161  registered in the second country wireless communication network  32  according to the present invention.  
         [0033]    When the MSC  14  of the first country wireless communication network  12  receives a message of calling the international roaming mobile station  161 , the MSC  14  of the first country wireless communication network  12  sends a message requesting location information of the mobile station  161  to the HLR  22 . When the HLR  22  receives the location information request message from the MSC  14 , the HLR  22  confirms the current location of the mobile station  161  based on the database thereof( 320 ). Then, the HLR  22  sends a routing request message  330  through IGW  50  to the MSC  34  currently registered by the mobile station  161 . When the routing request message is received, the MSC  34  assigns a routing number(for example, TLDN)  340  in response to the routing request message, and forwards the assigned routing number to the HLR  22 ( 350 ). When the routing number is received, the HLR  22  adds the international telephone service provider number  360 , such as “001”, “002”, “00755”, etc., which is stored in the user&#39;s profile of the mobile station  161  to the routing number  340 , and sends the added number to the MSC  24 . Since the process of establishing the call between the mobile station and a caller is the same as that of IS-41, the detailed description of the process is omitted.  
         [0034]    [0034]FIG. 4 is a signaling flow and network operation diagram illustrating the process of providing the call service to a mobile station  36  subscribed in the second country wireless communication network  32  according to the present invention when the mobile station  36  visits the first country wireless communication network  12 .  
         [0035]    When a mobile station  36  subscribed in the second country wireless communication network  32  visits a service area of a MSC  14  of the first country wireless communication network  12 , the mobile station  361  registers in MSC  14 . The MSC  14  assigns a prepared, predetermined domestic number(for example, TLDN) to the mobile station  361 . When the MSC  14  receives a routing request message  400  for the mobile station  361 , the MSC  14  determines whether the routing request message originates from MSCs of the first country communication network  12  or any foreign country communication networks for example, the HLR  42  of the second country wireless communication network  32 . When the routing request message is from the HLR  42  of the second country wireless communication network  32 , the MSC  24  generates an international routing number  410  and forwards the international routing number  410  (for connecting with the second country wireless communication network) to the HLR  42 ( 420 ). To the contrary, when the routing request message originates from the HLR  22  of the same system, the MSC  14  generates a domestic routing number(used in the first country)  410  and forwards the domestic routing number to the HLR  42 ( 420 ). Preferably, the international routing number includes the domestic routing number, a country code, and a domestic wireless communication service provider code.  
         [0036]    Further, when the visiting mobile station  361  initiates a call, the MSC  14  sends call connect message having the virtual origination number which is assigned to the mobile station  361  in registration instead of the real number of the mobile station  361 , such that confusion caused by a different number scheme between two countries is prevented.  
         [0037]    According to the present invention, the method allows the subscribers to select one international telephone service provider or more by themselves. Further, according to the present invention, the international roaming mobile stations can receive a wireless communication service regardless of the telephone number scheme differences between the countries.  
         [0038]    While this invention has been particularly shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.