Access‐agnostic 5G Core Network

As already stated, one of the goals of 5G networks is the minimization of any dependencies between
core and access networks. This is desired to enable access convergence among 3GPP, non‐3GPP
and fixed access networks. Such a convergence requires that the core and access networks are
evolved in an independent way. In other words, the CN has to be “agnostic” to the characteristics
and features of the access networks. Note that in previous 3GPP releases, similar goals were pursued
under the “access integration” design goal, achieving only a certain level of interworking. With the
design of “access‐agnostic” CNs, it is expected that a more flexible and future‐proof solution will be
achieved. To achieve this notion of access-agnostic core, three alternatives have been identified and
examined.
The first approach, illustrated in Figure 5‐11, impacts the 5G CN only. It requires the NF terminating
the AN/CN interface to be able to support all access networks (i.e., 5G RAN, LTE, Wi‐Fi,
etc.). In practical terms, this would require the definition of a convergence sub‐function of the
AMF. The advantage of this approach is that only the CN would be affected, and potentially all
legacy access networks could be integrated without any modification required on their side. This solution, however, would increase the system complexity, as multiple AN‐CN interfaces would.


Reference :

5G System Design
Architectural and Functional Considerations and Long Term Research