A CSP started 5G deployment with Option 3X. Now they want to start selling URLLC. What key components must be upgraded? {Select 2)

To offer Ultra-Reliable Low-Latency Communications (URLLC), a Communication Service Provider (CSP) must upgrade key network domains beyond the capabilities of a standard 5G NSA Option 3X deployment.
1. Core: The Option 3X architecture relies on a 4G Evolved Packet Core (EPC). The EPC is not designed for the stringent latency requirements of URLLC. An upgrade to a 5G Core (5GC) is mandatory. The 5GC's Service-Based Architecture (SBA) and its ability to place User Plane Functions (UPF) closer to the network edge are critical for minimizing end-to-end latency.
2. 5G RAN: The 5G Radio Access Network (RAN) also requires significant enhancements. Initial 5G deployments focus on eMBB. Supporting URLLC requires specific RAN features like mini-slot scheduling (to reduce transmission time), grant-free uplink access (to reduce signaling delay), and pre-emptive scheduling (to prioritize URLLC traffic over other traffic types).

B. UE: While URLLC-capable User Equipment (UE) is necessary for the end-to-end service, the question asks what the CSP must upgrade in its own infrastructure to begin selling the service. The Core and RAN are the primary network components under the CSP's control.
D. Cloud: This option is too generic. While the Core and RAN functions run on a cloud infrastructure, the specific upgrades are to the network functions themselves (Core and RAN software/architecture), not the underlying cloud platform in general.

1. Nokia Official Documentation: In the Nokia white paper, "5G network slicing for verticals," it is detailed that end-to-end network slicing, which is essential for guaranteeing URLLC performance, requires capabilities from the RAN, transport, and core domains. It states, "The 5G core network... introduces a new service-based architecture (SBA)... essential for creating and managing network slices." It also highlights RAN features like "semi-persistent and pre-emptive scheduling" for URLLC. (Nokia, "5G network slicing for verticals," 2020, Pages 4-6).

2. Academic Publication: A study published in IEEE Communications Surveys & Tutorials explains the architectural requirements for URLLC. The authors state, "To meet the stringent E2E latency requirement of URLLC services, both the 5G RAN... and the 5G core network (5GC) need to be enhanced." The paper details the necessity of the 5GC's UPF for edge deployment and specific RAN schedulers. (Saad, et al., "A Survey of Opportunities and Challenges in 6G: From Millimeter-Wave to Terahertz Communication," IEEE Communications Surveys & Tutorials, Vol. 22, Issue 1, 2020, Section IV-A, pp. 36-38. DOI: 10.1109/COMST.2019.2950401).

3. 3GPP Technical Specification (Vendor-Neutral Standard): The 3GPP TS 23.501 standard, "System architecture for the 5G System," defines the architecture required for services like URLLC. The entire specification is based on the 5G Core network, not the 4G EPC used in Option 3X. Section 5.33, "Support for Ultra-Reliable and Low Latency Communication," outlines specific functionalities within the 5GC and interactions with the NG-RAN that are prerequisites for URLLC. (3GPP TS 23.501, V16.7.0, Release 16, 2020, Section 5.33).