Subsystem 2 Subsystem 2 Frequency band#2 Figure 12.5 Hybrid deployment example over multifrequency bands. ((iii) ((1),) Emergency eMBB subsystem Vehicle subsystems subsystem1 subsystem2 subsystem Vehicle subsystem: utility (or MTC application) network Dedicated network slice (with Vehicular slice with both V2V slice with shared resources separate resources) and eMBB services Figure 12.6 Deployment scenarios of RAN parts of network slice. Scenario 3: hybrid deployment scenarios: In this hybrid example, incorporating the above two scenarios, different RAN subsystems can be supported within a single frequency band with multifrequency bands deployment, as in Figure 12.5. In 3GPP Release 15, it is assumed that UE supported network slices are homogeneously available in a single registration area including a tracking area list. However, for the above deployments, the RAN subsystem could be deployed even in a cell granularity. There is no strict relationship of registration area assignment and UE supported slices. Hence, this can highly increase the RAN deployment flexibility, and allow mobile operators to have lower OpEx and greater CapEx efficiency [8]. Overall, Figure 12.6 gives the deployment scenario. Specifically, some RAN subsystems could be deployed on lower frequency bands below 6 GHz, while other RAN subsystems could be supported on high frequency bands, e.g. above 24 GHz [12]. Also, it can be observed that some RAN subsystems may share com- mon radio resources while others would require dedicated and separate resources. 12.4 Key Technologies to Enable Service-Oriented RAN Slicing 12.4 Key Technologies to Enable Service-Oriented RAN Slicing To support a branded subsystem over a NG-RAN from the branded subsystem provided by the NG-RAN, the UE can obtain its "private" and specific services, e.g. potential vertical services. To achieve this, the 3GPP network needs to inform the UE of the correlations or mappings between the supported slices and the supported branded subsystems, e.g. via NAS or access stratum (AS) 