etwork deployment architectures The following is a general comparison of the 5G radio access and core networks (https://www. gsma.com/futurenetworks/wp-content/uploads/2018/04/Road-to-5 Introduction-and-Migration_FINAL.pdf): Advantages Disadvantages Radio access Simple to manage an intergenerational Not able to leverage existing LTE network handover between 4G and 5G deployments if NR is used in SA Leverage existing LTE deployments Tight interworking between LTE and NR required May impact end user experience Core network Leverage existing EPC deployments Cloud support is optional Cloud-native Easier to support New deployment required multiple access Figure 9.2 - Comparison of 5G radio access and core networks Let's talk more about those two architectures and focus on the main advantages and disadvantages of each one in a bit more detail. NSA network architecture NSA architecture exploits 4G and 5G radio access technologies at the same time, SO it combines the existing 4G RAN and EPC with the New Radio (NR) technologies of 5G to provide faster and more reliable service to its users. NSA architecture is the most common choice for existing MNOs who want to deliver high-speed connectivity to consumers with 5G-enabled devices. Moreover, NSA architecture helps MNOs leverage their existing 4G network to provide eMBB services with very low Capital Expenditures (CAPEX). In the NSA architecture, NR cells are combined with LTE cells to provide radio access with the dual connectivity concept. The core network choice can be either the 4G EPC or even 5GC depending on the investment and architecture choice of the operator. As a note, the architecture is still NSA even if 5GC is utilized instead of a 4G EPC since two radio access technologies are used simultaneously by the mobile user. 5G Deployment Options Control Plane Data Plane Figure 9.3 - NSA network architecture Now, let's talk a little bit more about this dual connectivity concept. Dual connectivity for NSA architecture Dual connectivity is also called Multi-Radio Access