2017/12 22 p.
The purpose of this study is as captured in the Study Item description document:
From TR 38.801, study the scenarios, the feasibility and the benefits of the separation of the CU-CP (control
plane instance of PDCP/RRC protocols) and the CU-UP (the user plane instance of PDCP (and SDAP)
Identifying details solutions e.g. introducing a standardised control plane interface between the CU-CP and CU-UP part of the gNB to enable the possibility of optimizing the physical location of different RAN functions
based on the scenario and desired performance.
Study the necessary protocol functions down to the procedure and message level related to the possible identified
solutions e.g. a standardised control plane interface to enable set-up, modification, and release of the DRB
related resources in the CU-UP, including handling of security keys in the CU-UP for RAN security activation
and configuration. This also needs to take the agreed F1 interface general principle, and gNB-CU/DU
architecture principle into account.