Patent ID: 7065356

Claim:
A method for preventing unauthorized use of roaming numbers in a wireless telecommunications system, said method comprising the steps of: receiving a call request for a mobile terminal at a Gateway Mobile Switching Center (GMSC); sending a request for routing information from said GMSC to a Home Location Register (HLR) associated with said mobile terminal; sending a request for a roaming number from said HLR to the Mobile Switching Center (MSC) associated with the roaming area in which said mobile terminal is geographically located: allocating, by said MSC, a roaming number for said mobile terminal; assigning, by said MSC, an authentication code to said roaming number; sending a response to said request for roaming number from said MSC to said HLR, said response including said roaming number and said authentication code; receiving said roaming number and said authentication code at said HLR; sending said roaming number and said authentication code from said HLR to said GMSC; sending a call setup request from said GMSC to said MSC, said call setup request including said roaming number and said authentication code; confirming, by said MSC, said authentication code in said call setup request; and, if said authentication code for said roaming number is confirmed by said MSC, completing said call request to said mobile terminal.