Systems, methods and media for enhanced circuit-switched fallback interworking function signaling procedures for roaming user equipment

A network device comprising:

• a memory capable of storing data;
• and
• a processor configured for using the data such that the network device can:
• receive from a home location register (HLR) a request to provide routing information for a user equipment (UE) for which an incoming voice call is received, wherein the request includes an identifier of the UE and wherein the UE is operating in a long term evolution (LTE) network;
• send a page signal along with a temporary mobile subscriber identity (TMSI) for the UE to a mobility management entity (MME) in the LTE network that can locate the UE, wherein the TMSI is allocated for the UE when the UE attaches to the LTE network and wherein the page signal causes the UE to switch to a legacy network, including a 3G network;
• detect a mobile switching center (MSC) that hosts the UE and is located in the legacy network;
• receive a mobile station roaming number (MSRN) for the UE from the hosting MSC;
• and
• send to the HLR a first message including the MSRN in response to the request such that the MSRN can be used to route the incoming voice call to the UE.

A computer program product residing on a non-transitory computer-readable medium, the computer program product comprising computer executable code which, when executed by one or more processors, causes the one or more processors to perform a method comprising:

• receiving at a circuit-switched fallback interworking function (CSFB-IWF) a request to provide routing information for a user equipment (UE) for which an incoming voice call is received, wherein the request is received from a home location register (HLR) and includes an identifier of the UE and wherein the UE is operating in a long term evolution (LTE) network;
• allocating at the CSFB-IWF a temporary mobile subscriber identity (TMSI) for the UE;
• sending from the CSFB-IWF a page signal along with a temporary mobile subscriber identity (TMSI) for the UE to a mobility management entity (MME) in the LTE network that can locate the UE, wherein the TMSI is allocated for the UE when the UE attaches to the LTE network and wherein the page signal causes the UE to switch to a legacy network, including a 3G network;
• detecting at the CSFB-IWF a mobile switching center (MSC) that hosts the UE and is located in the legacy network;
• receiving at the CSFB-IWF a mobile station roaming number (MSRN) for the UE from the hosting MSC;
• and
• sending from the CSFB-IWF to the HLR a first message including the MSRN in response to the request such that the MSRN can be used to route the incoming voice call to the UE.