tions In this table, we can see that Option 3 is the low-cost deployment option for MNOs to quickly commercialize 5G networks. With Option 7, the cost is high compared to Option 3 due to the implementation of 5GC. So far, we have examined SA and NSA network architectures. Let's now move on to the possible migration strategies for MNOs to move from 4G to 5G and from which options they should migrate first to ensure to fully exploit the 5G capabilities and use cases. 4G to 5G migration strategies The evolution from 4G to 5G can vary depending on an MNO's existing network status and strategy. First, remember that the control plane and UE signaling are managed by the master node, the eNB in NSA architecture with Option 3, while it is managed by the gNB in SA mode with Option 2. Since 5G coverage is very limited in the initial stage of 5G rollouts, the control plane is managed by eNBs with nationwide 4G coverage, and as the 5G coverage expands, the control plane can then be managed by gNBs. So, this is the essential consideration behind the 4G to 5G transition and migration strategy from an MNO's perspective: 5G Deployment Options NR NSA Option 3 Option 7 Easy 5GC migration Option 4 NR full coverage Quick time-to-market using eLTE full coverage Legacy LTE/EPC Hot spot deployment NR coverage expansion (with above 6 GHz NR) (with below 6 GHz NR) Local use cases (with above 6 GHz NR) Option 2 NR SA Figure 9.10 - 4G to 5G migration strategies Before introducing 5G, we assume that an MNO has an existing 4G network, covered by Option 1, which comprises an eNB and EPC. As discussed previously, Option 3 can be quickly deployed by upgrading the existing 4G nodes and deploying 5G gNBs, SO the introduction of 5G with Option 3 helps MNOs quickly commercialize 5G with a quick time-to-market and low CAPEX. However, since there is no utilization of 5GC, MNOs are limited to only providing eMBB services to their customers, but they will still provide very high user throughput due to the wide range of bandwidth for 5G and NR features. 