SWITCHING BETWEEN HIGH-SPEED DATA PACKET DATA CALL AND EITHER NON-HIGH-SPEED DATA CIRCUIT SWITCHED DATA CALL OR NON-HIGH-SPEED DATA PACKET DATA CALL

摘要

A method for moving from a 3G CDMA data session to a 2G circuit switched data session and vice versa. The high-speed packet data service option of IS-2000 (3G) does not support the older low-speed IS-95 traffic channels (2G). When a mobile station, having an established high-speed packet data service call, moves from an area of 3G coverage to an area where only 2G coverage is available or where mixed 2G/3G coverage is available and the 3G coverage is congested, the call is switched during this handoff from a 3G IS-2000 high-speed packet data service call to an IS-95 circuit switched data service call or an IS-707-A-5 low-speed packet data service option. The 3G call may also be terminated and re-established as an 2G call re-routed using Mobile IP. For switching the call, the base station controller signals to the packet data support mode that is must alter the protocol stack used in the R-P interface.