Page 95 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 3

A minimal system should be specified as the baseline that can serve the most basic use cases. Additional
functionality can then be added on demand as needed to serve more demanding use cases.

The communication (CP and UP) between UE and AN as well as any AN internal communication is access
specific. All other communication can be designed in an access independent fashion:
– The CP entity authenticates the subscriber and obtains the subscription information interacting with
an access independent subscriber repository and authentication function
– Following successful authentication, the CP entity informs the UP GW & Forwarder about the
permitted UP flows for this UE, based on the information obtained from the subscriber profile
– The User Plane GW & Forwarder function routes service data flows between AN and external Data
Network (e.g., Internet)
Additional CN functions (QoS, charging, etc.) beyond this baseline system are needed in more demanding
usage scenarios. Such additional CN control plane functions are enabled on demand, as required by the
specific customer use case.

It is thereby possible to configure e.g. the following CP functions per UE / flow:
– Quality of Service
– Charging

– Policy Control
– Mobility Management
– Session/Service Continuity (with or without intra-AN mobility, with or without AN change)
CN user plane functions associated with the active CP functions can be chained into the user plane path as
shown above.
NOTE – the above functions are examples only and are neither intended to define the overall functionality of
the network nor the granularity of the network functions.
NOTE – AF may be shared with external network, or exist exclusively within or outside of the operator
domain.
6.1.1.4 Gap Analysis (should be updated after further investigation)
– A network slice is an E2E concept including CN parts of the slice and RAN parts of the slice (3GPP
SA2 Interim Agreement)
• RAN slicing at 3GPP SA2 is out of scope
• RAN WGs at 3GPP have agreed not including slicing in phase 1 (Rel-15) due to many
consideration
– The right level of NF granularity is scope of phase 2 (Rel-16)

• The level of inter-dependency between network functions
• Need for independent scalability of individual network functions
• Need for deployment of individual network functions within or across operator network (e.g.,
PLMN) boundaries
• Need for supporting centralized or geographically distributed deployments
• Based on above, identification of the network functions for the next generation architecture
and definition of the set of functionalities supported by each of them
– Network capability exposure and APIs is scope of phase 2 (Rel-16)
• Define network capability exposure framework
• Identify the mechanisms and interfaces to expose network capabilities to the 3rd party and/or
UEs
• Identify the network information that can be provided to 3rd party ISPs/ICPs and to the UE to
enable more customized and efficient service provision

89