The architecture of the 5G mobile network is being developed in two stages: In the first development step, 5G uses the existing Long Term Evolution( LTE) infrastructure as a transition technology; in the second development step, an additional control layer and a user layer are implemented.
The first development step stands for 5G Non-Standalone (5G NSA) and uses the LTE core network with the Evolved Packet Core ( EPC) and the radio access network( RAN). At the user level, 5G NSA relies on 5G New Radio (5G NR) technology. The existing LTE infrastructure connects the LTE Evolved Packet Core (EPC) to the User Equipment ( UE) via the control plane of the LTE access technology, LTE RAN. This approach forms a combined solution using LTE access technology and LTE core network technology with the addition of a component carrier( CC).
The second development step, 5G Standalone(5G SA), is based on an additional user plane connecting the 5G Next Generation Core (5G NGC) to the subscriber equipment via the radio access network of 5G New Radio (5G NR RAN).