4G CUPS refers to 4G "Control and User Plane Separation". It is a 4G network architecture concept that was introduced in 3GPP Release 14 for 4G LTE networks.

In a traditional 4G LTE network architecture, the control plane (signaling), and user plane (data) functions, exist on the same network elements. While using 4G CUPS, it separates between these functions. This allows the control plane and user plane, to exist as independent network functions.

By separating the control and user plane, the network can scale these functions independently based on the specific demands and requirements. This allows for more efficient use of network resources, and the ability to optimise the control and user plane functions separately.