System and method for providing IP version interworking for IMS access through EPC

A Packet Data Network Gateway (PGW) network node of an Evolved Packet Core (EPC) for connecting a User Equipment (UE) with an IP Multimedia Core Network Subsystem (IMS), comprising:

• a Gx interface toward a Policy Control and Charging Rules Function (PCRF) network node configured to transmit an Internet Protocol version 4 (IPv4) address, allocated to the UE by the PGW, to the PCRF;
• an SGi interface toward an application node of the IMS configured to transmit the IPv4 address to the application node, and to transmit and receive IP media packets between the IMS and the UE after IPv4 and Internet Protocol version 6 (IPv6) address translation by the PGW;
• and
• a processor including:
• an Internet Protocol (IP) address assignment function configured to allocate on a per Package Data Network (PDN) basis, to the UE requesting an IPv6 address, both of (a) the IPv4 address from an IPv4 address pool, and (b) the IPv6 address from an IPv6 address pool;
• a Network Address Translation-Application Layer Gateway (NAT64-ALG) function configured to translate between IPv4 and IPv6 addresses of the UE;
• and
• one or more of an S2b interface toward an Evolved Packet Data Gateway (ePDG) network node, an S5/S8 interface toward a Serving Gateway (SGW) network node, and an Gn/Gp interface toward a Serving GPRS Support Node (SGSN) network node,
• wherein the PGW sets up a dedicated tunnel between an Evolved Packet Data Gateway (ePDG) network node and the PGW.

A computer-implemented method in a Packet Data Network Gateway (PGW) of an Evolved Packet Core (EPC) for interfacing with an IP Multimedia Core Network Subsystem (IMS), comprising:

• allocating, on a per Package Data Network (PDN) basis, to a User Equipment (UE) requesting an IPv6 address, both of (a) an Internet Protocol version 4 (IPv4) address from an IPv4 address pool, and (b) the IPv6 address from an IPv6 address pool;
• providing IPv4 and IPv6 address and Service Data Flow (SDF) filter translation;
• providing a Gx interface toward a Policy Control and Charging Rules Function (PCRF) network node configured to transmit the UE's IPv4 address to the PCRF;
• providing an SGi interface toward an application node of the IMS, providing the UE's IPv4 address to the application node over the SGi interface, and transmitting and receiving IP media packets between the IMS and the UE after IPv4 and IPv6 address translation;
• providing one or more of an S2b interface toward an Evolved Packet Data Gateway (ePDG) network node, an S5/S8 interface toward a Serving Gateway (SGW) network node, and an Gn/Gp interface toward a Serving GPRS Support Node (SGSN) network node;
• and
• receiving a Protocol Configurations Option (PCO) message comprising an IP version of the UE from the UE.