Patent ID: 8331979

Claim:
An access network selection method in a communications network where multiple operators have respective networks and each of the networks includes multiple access networks, the access network selection method comprising: transmitting a signal of a call originating request including a service type to a called-side terminal by a calling-side terminal; selecting a visited network available to the called-side terminal among the networks managed by the different operators in accordance with the service type, including the selection result in the call originating request, and transmitting the call originating request to the called-side terminal by a home network of the called-side terminal having received the call originating request; notifying a device in the called-side visited network of an identifier of an available one or more of the access networks in the selected visited network and a user preference by the called-side terminal having received the call originating request; transmitting a list of candidates for an access network to be assigned to the called-side terminal to a device in a calling-side network by the device in the called-side visited network; selecting one of multiple visited networks available to the calling-side terminal in accordance with the service type and notifying the calling-side terminal of the selection result by a home network of the calling-side terminal having received the list; notifying a device in the calling-side visited network of an identifier of an available one or more of the access networks in the selected one of the visited networks and a user preference by the calling-side terminal having received the selection result; determining an access network to be assigned to the calling-side terminal and notifying a called-side network of the determined access network by the device in the calling-side visited network; determining the access network to be assigned to the called-side terminal and notifying the called-side terminal of the determined access network by the device in the called-side visited network; notifying the calling-side terminal of the access network assigned to the called-side terminal by one of the called-side terminal and the device in the called-side visited network; determining the access network to be assigned to the calling-side terminal and notifying the calling-side terminal of the determined access network by the device in the calling-side visited network; and notifying the called-side terminal of a type of the access network assigned to the calling-side terminal by one of the calling-side terminal and the device in the calling-side visited network.