E1 interface setup in ng-ran

An apparatus of a next generation NodeB (gNB), the apparatus comprising:

• processing circuitry;
• and memory,
• wherein the gNB is configured with logical nodes including a gNB central unit (gNB-CU) and a gNB distributed unit (gNB-DU), the gNB-CU comprising a gNB-CU control plane (gNB-CU-CP) for control-plane functionality and a gNB-CU user plane (gNB-CU-UP) for user-plane functionality, the gNB-CU-CP configured to communicate with the gNB-CU-UP over an E1 interface, the gNB-CU-UP configured to communicate user plane messages with the gNB-DU over an F1 user-plane interface (F1-U), the gNB-CU-CP is configured to communicate control plane messages with the gNB-DU over an F1 control plane interface (F1-C),
• the processing circuitry configured to:
• initiate, by one of the gNB-CU-CP and gNB-CU-UP, a first Transport Network Layer (TNL) association between the gNB-CU-CP and gNB-CU-UP;
• limit establishment of an E1 interface between the gNB-CU-CP and gNB-CU-UP to the one of the gNB-CU-CP and gNB-CU-UP;
• and
• after the first TNL association is operational, initiate an E1 Setup procedure to set up the E1 interface;
• and
• a memory configured to store information of the E1 Setup procedure.

An apparatus of a central unit control plane of a next generation NodeB (gNB-CU-CP), the apparatus comprising:

• processing circuitry configured to:
• initiate a first Transport Network Layer (TNL) association between the gNB-CU-CP and a central unit user plane (gNB-CU-UP);
• and
• after the first TNL association is operational, initiate an E1 Setup procedure to set up an E1 interface between the gNB-CU-CP and gNB-CU-UP,
• wherein establishment of the E1 interface is limited to the gNB-CU-CP and comprises:
• transmission of a GNB-CU-CP E1 SETUP REQUEST message, and
• determination that setup of the E1 interface is successful in response to reception of a message that contains information elements (IEs) of a GNB-CU-CP E1 SETUP RESPONSE message in response to transmission of the GNB-CU-CP E1 SETUP REQUEST message;
• and
• a memory configured to store the IEs of the GNB-CU-CP E1 SETUP REQUEST message.