Enhanced signaling to reduce no circuit switch fallback

A method comprising:

• sending, from a proxy call session control function (PCSCF) to a policy charging rules function (PCRF), an authorization and addressing request (AAR) associated with a voice over long term evolution (VoLTE) call for a user equipment (UE);
• receiving, at the PCSCF from the PCRF, an error code indicating that a first Gx binding is unavailable;
• retrieving, with the PCSCF, a name of a packet gateway (PGW) associated with the UE from a PGW name lookup;
• retrieving, with the PCSCF, an internet protocol (IP) address associated with the name of the PGW from a PGW IP lookup;
• sending, from the PCSCF to the PCRF, an attribute value pair (AVP) message including the IP address of the PGW associated with the UE and causing the PCRF to initiate a second Gx binding;
• receiving, at the PCSCF and from the PCRF, an indication that the PCRF failed to initiate the second Gx binding;
• sending, from the PCSCF to the PGW, instructions to cause the PGW to establish a Gx session with the PCRF;
• and
• sending, from the PCSCF to the PGW, a session request AVP message to cause the PGW to initiate the second Gx binding.

A system comprising:

• a proxy call session control function (PCSCF) comprising:
• one or more transceivers;
• memory storing at least a Gx backup algorithm and a packet gateway (PGW) name lookup;
• and
• one or more processors in communication with the one or more transceivers and the memory, the Gx backup algorithm causing the PCSCF to:
• send, with the one or more transceivers, an authorization and addressing request (AAR) to a policy charging rules function (PCRF) to establish a voice over long term evolution (VoLTE) call for a user equipment (UE);
• receive, with the one or more transceivers, an error message from the PCRF indicating that a first Gx binding is unavailable;
• determine, with the one or more processors and in response to the error message, information to initiate second Gx binding, the information including at least one of a PGW name from the PGW name lookup or a PGW Internet protocol (IP) address;
• send, with the one or more transceivers to the PCRF, the information to initiate the second Gx binding between the PCRF and a PGW associated with the UE;
• and
• send, from the PCRF to the PGW, a session request attribute value pair (AVP) message to cause the PGW to initiate the second Gx binding.