Implementing MATRIXX on an EPC/5GC Hybrid Core Network

If your environment uses a Policy Control Function (PCF)/Policy and Charging Rules Function (PCRF) combination, you can configure MATRIXX to create a 5G session and as circumstances require, switch it to a 4G session or to create a 4G session and switch it to a 5G session. This strategy requires your subscribers to use dual-core evolved packet core (EPC)/5G user equipment.

Figure 1 shows a hybrid network set up to use both 4G and 5G capabilities. These diagrams show Subscriber A served by a hybrid EPC/5GC network and Subscriber B served by a legacy EPC. Both subscribers have open sessions.
Figure 1. Subscriber Session Using a 5G Network
Note: In mixed mode operation, no direct dependency exists between the 3G/4G and 5G protocols. Diameter Gy and N40 charging requests simply update the state of subscriber and balance databases. The Charging Server then notifies the respective PCF/PCRF client of changes to those databases over either N28 or Sy. The source could be Gy, N40, or even subscriber-management offer purchases, balance adjustments, and so forth.