Patent ID: 10004003

Abstract:
A method for switch user equipment from a Long Term Evolution system to a Circuit Switched system when receiving a voice call is disclosed. The method may comprise: receiving, at an IWF (Internet Working Function) network node, a Mobility Application Part Unstructured Supplementary Service Data (MAP USSD) message identifying a User Equipment (UE) originated from a USSD application, the UE associated with a first Mobile Switching Center (MSC); initiating Circuit Switched Fallback (CSFB) by sending a paging request to the UE; receiving a Cancel Location message associated with the UE from a Home Location Register (HLR) indicative of the UE being associated with a second MSC; forwarding the MAP USSD message to the UE via the HLR and the second MSC; receiving a MAP USSD response message from the UE via the HLR; and forwarding the MAP USSD response message to the USSD application.