IWF for MVNO - 3G to 4G conversion

IWF or Interworking Working Function is a node in the GSM network. IWF provides a conversion for 4G to 3G and 3G to 4G signaling.  We are providing a software solution for IWF over Diameter and SS7/Sigtran for MVNOs. 

Why need to IWF?

There is a need to support 4G sim cards for faster mobile data. The 3G MVNO have all subscribers in HLR. If a 3G MVNO wants to support 4G SIM cards an HSS is required. This may change the existing subscribers’ storage and may incur a huge cost. But MVNO needs to go for the 4G upgrade. 
With the IWF for 3G MVNO, there will be no change the 4G to 3G signaling conversion will be done by the IWF. 

How 4G to 3G IWF works for an MVNO?

The IWF is deployed as standalone software on a Linux machine.  On one side, IWF will connect to the Diameter DRA for 4G signaling and to MVNO it connects to SS7/Sigtran for GSM MAP ss7 signaling.  Any communication between the 4G device and HLR will be via IWF. The IWF will be transparent to the MVNO HLR.