Network Slicing (and related) Features in 3GPP 5G Use Case Team

E2E Slicing NSSF NRF AMF SMF UPF UPF UE gNB SMF UPF UPF Network Slice: A logical network that provides specific network capabilities and network characteristics. Network Slice instance: A set of Network Function instances and the required resources (e.g. compute, storage and networking resources) which form a deployed Network Slice. High level constraints: UE can access up to 8 slices via distinct PDU sessions (one PDU session can belong to only one slice) Same AMF serves as control anchor for a given UE for all slices UE can access 5G-RAN is conceptualized simply as “slice-aware” THIS VIEW IS LOGICAL: Where and how the individual functions are deployed, how resources are shared or dedicated not specified. N22 NSSF NRF AMF N11 SMF N1 N2 N4 SLICE X UPF UPF N3 UE gNB AMF: Access and Mobility Management Function SMF: Session Management Function UPF: User Plane Function NSSF: Network Slice Selection Function NRF: NF Resource Function N3 SMF 5G-RAN N4 SLICE Y UPF UPF

High Level Process for Slice Access Slice Information is carried and used in: UE to AMF PDU Session Request SMF selection procedure (may involve NSSF and NRF) Subscription retrieval by SMF Notifications by UDM SMF to AMF Message for PDU session context set up AMF to RAN Session Request Slice identification & selection: Done via S-NSSAI and NSSAI S-NSSAI is comprised of Slice/Service type (SST) and a Slice Differentiator (SD) PDU Session Context in SMF, AMF, and RAN has 1-1 association between PDU session and S-NSSAI Slice/Service Type SST value Characteristics. eMBB   1 Slice suitable for the handling of 5G enhanced Mobile Broadband. URLLC 2 Slice suitable for the handling of ultra- reliable low latency communications. MIoT 3 Slice suitable for the handling of massive IoT.

Processing inside 5G-RAN L2-Downlink with Carrier Aggregation L2-Uplink with Carrier Aggregation Individual carriers Ref. 3GPP TS 38.300

RAN Slicing Concepts (3GPP TS 38.300) RAN awareness of slices Differentiated handling of traffic for different network slices Selection of RAN part of the network slice Using UE or CN provided assistance information Resource management between slices Policy enforcement between slices as per service level agreements for each supported slice Support of QoS (within Slice) RAN selection of CN entity Selecting AMF for UE attachment (same AMF handles all slices that UE accesses) Resource isolation between slices Implementation dependent. Resources can be shared or dedicated. If shared RRM policies and protection mechanisms should be implemented. Slice Availability Local availability in parts of the network is supported. Slice availability should not change within UE’s registration area. Support for UE associating with multiple network slices simultaneously One signalling connection is maintained. Granularity of slice awareness (per PDU session) Validation of the UE rights to access a network slice Mainly dictated by 5GC policies. NG-RAN may be allowed to apply local policies based on RAN awareness of the slice.

RAN Constraints (Related to Slicing) in 3GPP Rel 15 Slice availability S-NSSAI (i.e., slice) must be supported in all cells in a UE’s registration area Change in supported NSSAI for Tracking Areas (TAs) induces UE re-registration Bandwidth Part (BWP) Each UE can have up to 4 BWP configured and only one is active at a given time Each BWP can be configured with a particular numerology Supported set of numerologies depend on the carrier frequency of BWP Slot Format Each slot is configured as one of 61 different UL-DL symbol allocation including flexible symbols (i.e., can be used for UL or DL based on scheduling) Different slot formats can be concatenated Can be modified by setting configuration parameters on UE side Flexible symbols are set as UL/DL using Download Control Information (DCI) NSSAI: Network Slice Selection Assistance Information S-NSSAI: Single Network Slice Assistance Information

Processing Slice Request Generate S-NSSAI Descriptor Request Analysis New Slice Slice Synthesis Slice Onboarding Operationalize Slice Lifecycle Management Slice Request Onboard/Configure 5G Functions with new S-NSSAI Manage Slice States, Policies, & Resources Grant Access to an existing S-NSSAI Data Collection Data Collection 5G CLOUD Infrastructure and Functions

E2E 5G Slice Dimensions Slice Descriptor UE Profiles CN Function (i.e., AMF, SMF & UPF) Cloud Selection Coverage CN Function Instantiation, Configuration, Selection Mobility Performance Requirements S-NSSAI RAN Selection (i.e., gNBs) Traffic Characteristic RAN Function (L2) Instantiation, Configuration, Selection Transport mode(s) & constraints Power Constraints Radio Link (L1) Configuration Carrier & BWP Slot Format Numerology Application Stack

For Casablanca? Assume 5G VNF/PNF instances are already onboarded Each VNF/PNF in the ONAP inventory has a supported NSSAI profile Before UE /CPE registration, 5G slice must be instantiated by ONAP ONAP constructs slice descriptor based on slice order, correlates the descriptor with the supported NSSAIs, picks a target NSSAI for the customer placing the slice order Instantiate and/or configure the functions for the target NSSAI E.g., update user subscription profiles and NSSF Trigger UE/CPE re-registration for UE/CPE start consuming the instantiated slice

Thank You!

Appendix - Numerology and Slot Length Radio Frame (10 ms) Subframe (1ms) Slot 62.5us to 1ms Supported Numerologies 1 ms 0.5 ms 250 us 125 us 62.5 us Control only no data 1 slot = 14 Symbols (Normal), 12 Symbols (Extended)

Appendix – Slot Format (3GPP TS 38.211) Symbol number in a slot 1 2 3 4 5 6 7 8 9 10 11 12 13 D U X 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 – 255 Reserved D: Downlink-only Symbol U: Uplink-only Symbol X: Flexible Symbol that can be scheduled for both UL & DL