Voice session handover between mobile networks with different network technologies

An apparatus comprising:

• a receiver that receives a handover message comprising first information indicating a voice handover request to handover a voice session from a first network to a second network;
• a processor that determines a first network function configured to facilitate communication with the second network, wherein the first network function comprises a mobile management entity that communicates with a core network of the second network without at least connecting to an evolved packet core and bearer splitting functionality;
• and
• a transmitter that transmits, to the first network function, a relocation request comprising second information related to the voice handover request;
• wherein:
• the receiver receives, from the first network function, a relocation response indicating completion of a voice handover;
• and
• the first network comprises a different mobile network technology than the second network.

A method comprising:

• receiving, at a single radio voice call continuity interworking function, a handover message comprising first information indicating a voice handover request to handover a voice session from a first network to a second network, wherein the single radio voice call continuity interworking function comprises a mobile management entity that communicates with a core network of the second network without at least connecting to an evolved packet core and bearer splitting functionality;
• mapping security context information to second information used by the second network;
• and
• selecting, via the single radio voice call continuity interworking function, a mobile switching center server configured to facilitate voice handover in the second network based on the first information.

An apparatus comprising:

• a receiver that receives, at a single radio voice call continuity interworking function, a handover message comprising first information indicating a voice handover request to handover a voice session from a first network to a second network, wherein the single radio voice call continuity interworking function comprises a mobile management entity that communicates with a core network of the second network without at least connecting to an evolved packet core and bearer splitting functionality;
• and
• a processor that:
• maps security context information to second information used by the second network;
• and
• selects, via the single radio voice call continuity interworking function, a mobile switching center server configured to facilitate voice handover in the second network based on the first information.