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

2. 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

3. 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.

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

5. 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.

6. 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

7. 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

8. 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

9. 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

10. Thank You!

11. 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)

12. 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