Method of handover of circuit-switched voice call to packet-switched voice call

摘要

A method, for example, is described in the present application. Such a method can include detecting or establishing a circuit-switched call. The method can also include establishing a voice-over-internet-protocol standby call in parallel to the circuit-switched call. The method can additionally include activating the voice-over-internet-protocol standby call to become an active voice-over-internet protocol call when a handover situation is detected. The method can further include releasing resources of the circuit-switched call when the voice-over-internet-protocol standby call becomes the active voice-over-internet protocol call.

主权项

1. A method comprising:
detecting or establishing a circuit-switched call over a cellular network; establishing, over a cellular network, a voice-over-internet-protocol standby call in parallel to the circuit-switched call, wherein the voice-over-internet-protocol standby call is a standby, virtual call that includes an established end-to-end signaling path but utilizes no physical radio resources, wherein the end-to-end signaling path is ready for use after a cellular handover situation to an active voice-over-internet protocol call established using the end-to-end signaling path; detecting the cellular handover situation; when the detected cellular handover situation is to a first type of network:
activating the voice-over-internet-protocol standby call to become the active voice-over-internet protocol call, andreleasing resources of the circuit-switched call, when the active voice-over-internet protocol call is established; and when the detected cellular handover situation is to a second type of network, wherein the second type of network is different from the first type of network:
performing the cellular handover using dual transfer mode signaling, andmaintaining the voice-over-internet protocol standby call in a standby state.