Patent ID: 8452278

Claim:
A method for facilitating inter-PLMN (Public Land Mobile Network) roaming, comprising: a home PLMN of a caller's wireless communication device determining that the caller's wireless communication device is not located in the home PLMN; facilitating a call routing service in a Service Control Point (SCP) of the home PLMN in response to determining that the caller's wireless communication device is not located in the home PLMN, wherein the call routing service causes a call originated by the caller's wireless communication device while roaming in a visited PLMN to be routed back to a Gateway Mobile Switching Center (GMSC) of the home PLMN thereby allowing the home PLMN to have control over said roaming caller originated call and to have limited dependency on the visited PLMN; and the GMSC of the home PLMN validating a Routing Number (RN) against configured Network Camel Subscription Information (N-CSI) in response to the home PLMN receiving said roaming caller originated call from the visited PLMN, wherein the RN is used for routing said roaming caller originated call from the visited PLMN to the home PLMN; wherein facilitating the call routing service includes: a home Location Register (HLR) of the home PLMN inserting call routing Originating Camel Subscription Information (O-CSI) into an insert Subscriber Data (ISD) message in response to determining that the caller's wireless communication device is not located in the home PLMN; sending the ISD message from the home PLMN for reception by a MSC of the visited PLMN in response to inserting the call routing O-CSI into the ISD message; sending call routing Initial Detection Point (IDP) information from the MSC of the visited PLMN for reception by the SCP of the home PLMN in response to accessing the call routing O-CSI; the SCP of the home PLMN assigning the RN to said roaming caller originated call in response to receiving said call routing IDP information whereby the RN is used as a routing prefix to route said roaming caller originated call from the visited PLMN to the GMSC of the home PLMN and as an index for retrieving an International Mobile Subscriber Identity (IMSI) of the caller's wireless communication device and a called party number; and sending the RN from the SCP of the home PLMN for reception by the MSC of the visited PLMN.