Different deployment scenarios have been considered by different bodies, namely 3GPP, the Small
Cell Forum (SCF), the Next Generation Fronthaul Interface (NGFI) forum, and NGMN, among others.
3GPP defines four main deployment scenarios as follows [5]:
Non‐centralized deployment, where the full protocol stack is supported by a gNB as in a macro
or indoor hotspot environment (which could include public or enterprise environments), which
can be connected to other gNBs and/or (e)LTE eNBs
Co‐sited deployment, where the NR functionality is co‐sited with (e)LTE functionality either as
part of the same BS or in the form of multiple BSs at the same site
Centralized deployment, where NR should support centralization of the upper layers of the NR
radio stacks with different split options between CUs and DUs
Shared RAN Deployment, where NR should support RAN sharing of multiple network operators
that have individual CNs but share spectrum or radio resources.
The Reference :
5G System Design
Architectural and Functional Considerations and Long Term Research
