Patent ID: 6597910
Filing Date: 2003-07-22
Classification: H04W

Abstract:
A method for performing the network direct system selection (NDSS) of a mobile station (MS) in a cellular communications system to connect said MS from one network to another network, comprising the steps of:(a) transmitting, by said MS, a CM SERVICE REQUEST to be transferred to a first mobile switching center (MSC) in said one network; (b) inserting, by a base station (BS), a dialed phone number intended for said NDSS to request a specific feature in said CM SERVICE REQUEST message prior to the transmission to said first MSC; (c) transmitting a FEATURE REQUEST INVOKE message, by said MSC, to a home location register (HLR) upon receiving said CM SERVICE REQUEST for said NDSS; (d) transmitting a FEATURE REQUEST INVOKE CONFIRMATION message, by said first MSC, to said MS via said BS; (e) upon receiving said FEATURE REQUEST INVOKE message, transmitting, by said HLR, a QUALIFICATION DIRECTIVE message that includes a service re-direction information to a first visitor location register (VLR) coupled to said first MSC; (f) confirming, by said first VLR, whether said QUALIFICATION DIRECTIVE message includes said service re-direction information; (g) transmitting, by said first VLR, a SERVICE RE-DIRECTION message to said MS via said BS, said SERVICE REDIRECTION message including said service re-direction information and a command requesting said MS to report if said MS fails to connect to a second MSC in said another network; and, (h) registering the location of said MS in a second VLR of said second MSC of said another network in response to said SERVICE RE-DIRECTION message.