node: LTE Core LTE Core LTE Core (EPC) (EPC) (EPC) 5G RAN LTE RAN LTE RAN 5G RAN LTE RAN 5G RAN LTE RAN 5G RAN LTE Core LTE Core LTE Core LTE Core LTE Core (EPC) (EPC) (EPC) (EPC) (EPC) LTE RAN 5G RAN LTE RAN 5G RAN LTE RAN 5G RAN LTE RAN 5G RAN LTE RAN 5G RAN Figure 9.5 - Different 5G options defined by 3GPP So these are the main differences - we will not go deep into the details of the other differences between these architectures. Let's now have a better view of the options from the SA and NSA perspectives. SA options There are three main variations of SA options within the 3GPP 5G deployment options. Firstly, Option 1, which wasn't mentioned previously, uses an eNB and the EPC. This is the existing LTE network and it is an SA architecture. Option 2 uses 5GC with a gNB: The different 5G deployment options defined by 3GPP Standalone LTE under EPC Standalone NR under SGC Standalone LTE under SGC (option 1) (option 2) (option 5) Figure 9.6 - SA options Note that this is the target architecture for 5G deployments as an SA option, considering there will be enough 5G coverage. The last main SA architecture is Option 5, which uses 5GC together with an ng-eNB. NSA options Option 3 (with 3a and 3x) is one of the most popular NSA options for 5G deployments, as we discussed already. Option 3 utilizes the EPC as the core network, and it consists of the eNB as the master node and the gNB as the secondary node. The importance of this option is that it helps MNOs to quickly deploy and commercialize 5G with smaller CAPEX compared to an end-to-end 5G network deployment. The drawback of this option is that it limits the IMT-2020 use cases to eMBB only. However, MNOs have the opportunity to exploit a broad bandwidth range of 5G, some NR features, and massive Multiple Input Multiple Output (MIMO) capabilities, which result in greater user throughput in total. So, let's move to the next option, which is Option 7 (with 7a and 7x). So, with this option, 5GC is introduced and connected to both the ng-eNB and gNB. Note that here, we d