Separation of control plane and user plane in new radio (NR) systems
Embodiments of a Next Generation Node B (gNB) are described herein. The gNB may be configured with logical nodes, including a gNB central unit (gNB-CU) and a gNB distributed unit (gNB-DU). The gNB-CU may include 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 may initiate an E1 interface setup procedure, a bearer context setup procedure, and a UE context setup procedure to establish a UE context that includes a signaling radio bearer (SRB) and a data radio bearer (DRB) configuration. The UE context setup request message may be configured to include quality-of-service parameters for the DRB configuration.
1. An apparatus comprising:
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, 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 configured to communicate control plane messages with the gNB-DU over an F1 application protocol (F1-AP) used on an F1 control plane interface (F1-C), wherein the apparatus is configured to:
transmit or receive first messages according to an E1 application protocol (E1-AP), the first messages including:
a GNB-CU-UP E1 setup request message from the gNB-CU-UP to the gNB-CU-CP, wherein the E1 setup request message includes a gNB-CU-UP ID that is at least a local ID;
a radio bearer configuration message from the gNB-CU-CP to the gNB-CU-UP over the E1 interface to configure one or more data radio bearers (DRBs), wherein the radio bearer configuration message includes a user equipment ID and a DRB ID;
a reset message over the E1 interface from the gNB-CU-UP to the gNB-CU-CP or from the gNB-CU-CP to the gNB-CU-UP;
an error indication message over the E1 interface from the gNB-CU-UP to the gNB-CU-CP indicating a cause of the error;
transmit or receive second messages according to the F1-AP, the second messages including:
a UE context setup request message from the gNB-CU-CP to the gNB-DU over the F1-C, wherein the UE context setup message is configured to include quality-of-service parameters;
a UE context modify message from the gNB-CU-CP to the gNB-DU over the F1-C, wherein the UE context modify message is configured to include quality-of-service parameters;
a UE context release message from the gNB-CU-CP to the gNB-DU over the F1-C; and
an uplink radio-resource control (RRC) message including a PDCP-PDU from the gNB-DU to the gNB-CU-CP over the F1-C.
2. The apparatus of claim 1 , wherein the gNB-DU is configured to host radio-link control (RLC), medium-access control (MAC) and physical (PHY) layers of the gNB, and wherein the gNB-DU is configured to communicate with user equipment over a user interface (uu).
3. The apparatus of claim 1 , wherein a bearer context setup procedure is performed after completion of an E1 interface setup procedure.
4. The apparatus of claim 1 , wherein the apparatus is further configured to transfer an RRC message as a downlink (DL) Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) to the gNB-DU from the gNB-CU-CP over the F1-C.
5. The apparatus of claim 1 , wherein the UE context setup request message further includes one or more of: an aggregate maximum bit rate (AMBR), a latency, a bit error rate, and a packet error rate.
6. The apparatus of claim 1 , wherein the UE context modify request message includes an updated value of one of the parameters of the UE context setup request message.
7. The apparatus of claim 1 , wherein the UE context release request message indicates that a DRB is to be released.
8. The apparatus of claim 1 , wherein the gNB-CU-CP is configured to send to the gNB-CU-UP, a second UE context setup request message that includes an access stratum (AS) security key for encryption and decryption of data packets of a DRB.
9. The apparatus of claim 1 , wherein the apparatus is further configured to:
receive, from a core network (CN), control signaling that indicates that the UE is to be paged for reception of a downlink data packet; and
send to the gNB-DU, a paging configure message that indicates: a paging identity of a UE, or a paging occasion of in which the UE is to be paged.
10. The apparatus of claim 1 , wherein the apparatus is further configured to:
send to the gNB-DU for broadcast, minimum system information (SI) that includes a master information block (MIB) and a type 1 SI block (SIB-1).
11. The apparatus of claim 1 , wherein the apparatus is further configured to:
receive, from the gNB-DU, a request from a UE for on-demand system information (SI) related to a capability of the UE to camp on a cell that includes the disaggregated gNB; and
send to the gNB-DU on the F1 interface, a downlink RRC message transfer that includes the on-demand SI.
12. The apparatus of claim 1 , wherein the apparatus is further configured to:
receive, from the gNB-DU, an uplink RRC message transfer that includes one or more measurement reports or a response to an RRC connection request from the UE; and
send to the gNB-DU on the F1 interface, a downlink RRC message transfer to configure, reconfigure, or release an RRC connection at the UE.
13. A Next Generation Node B (gNB) comprising:
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, 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 configured to communicate control plane messages with the gNB-DU over an F1 application protocol (F1-AP) used on an F1 control plane interface (F1-C), wherein the apparatus is configured to:
transmit or receive first messages according to an E1 application protocol (E1-AP), the first messages including: a GNB-CU-UP E1 setup request message from the gNB-CU-UP to the gNB-CU-CP, wherein the E1 setup request message includes a gNB-CU-UP ID that is at least a local ID;
a radio bearer configuration message from the gNB-CU-CP to the gNB-CU-UP over the E1 interface to configure one or more data radio bearers (DRBs), wherein the radio bearer configuration message includes a user equipment ID and a DRB ID;
a reset message over the E1 interface from the gNB-CU-UP to the gNB-CU-CP or from the gNB-CU-CP to the gNB-CU-UP;
an error indication message over the E1 interface from the gNB-CU-UP to the gNB-CU-CP indicating a cause of the error;
transmit or receive second messages according to the F1-AP, the second messages including:
a UE context setup request message from the gNB-CU-CP to the gNB-DU over the F1-C, wherein the UE context setup message is configured to include quality-of-service parameters;
a UE context modify message from the gNB-CU-CP to the gNB-DU over the F1-C, wherein the UE context modify message is configured to include quality-of-service parameters;
a UE context release message from the gNB-CU-CP to the gNB-DU over the F1-C; and
an uplink radio-resource control (RRC) message including a PDCP-PDU from the gNB-DU to the gNB-CU-CP over the F1-C.
14. The gNB of claim 13 , wherein a bearer context setup procedure is performed after completion of an E1 interface setup procedure.
15. The gNB of claim 13 , wherein the gNB is further configured to transfer an RRC message as a downlink (DL) Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) to the gNB-DU from the gNB-CU-CP over the F1-C.
16. The gNB of claim 13 , wherein the UE context setup request message further includes one or more of: an aggregate maximum bit rate (AMBR), a latency, a bit error rate, and a packet error rate.
17. A method for operating a Next Generation Node B (gNB) comprising:
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, 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 configured to communicate control plane messages with the gNB-DU over an F1 application protocol (F1-AP) used on an F1 control plane interface (F1-C), wherein the method comprises:
transmitting or receiving first messages according to an E1 application protocol (E1-AP), the first messages including: a GNB-CU-UP E1 setup request message from the gNB-CU-UP to the gNB-CU-CP, wherein the E1 setup request message includes a gNB-CU-UP ID that is at least a local ID;
a radio bearer configuration message from the gNB-CU-CP to the gNB-CU-UP over the E1 interface to configure one or more data radio bearers (DRBs), wherein the radio bearer configuration message includes a user equipment ID and a DRB ID;
a reset message over the E1 interface from the gNB-CU-UP to the gNB-CU-CP or from the gNB-CU-CP to the gNB-CU-UP;
an error indication message over the E1 interface from the gNB-CU-UP to the gNB-CU-CP indicating a cause of the error;
transmitting or receiving second messages according to the F1-AP, the second messages including:
a UE context setup request message from the gNB-CU-CP to the gNB-DU over the F1-C, wherein the UE context setup message is configured to include quality-of-service parameters;
a UE context modify message from the gNB-CU-CP to the gNB-DU over the F1-C, wherein the UE context modify message is configured to include quality-of-service parameters;
a UE context release message from the gNB-CU-CP to the gNB-DU over the F1-C; and
an uplink radio-resource control (RRC) message including a PDCP-PDU from the gNB-DU to the gNB-CU-CP over the F1-C.
18. The method of claim 17 , wherein a bearer context setup procedure is performed after completion of an E1 interface setup procedure.
19. The method of claim 17 , wherein the method further comprises transferring an RRC message as a downlink (DL) Packet Data Convergence Protocol (PDCP) Protocol Data Unit (PDU) to the gNB-DU from the gNB-CU-CP over the F1-C.
20. The method of claim 17 , wherein the UE context setup request message further includes one or more of: an aggregate maximum bit rate (AMBR), a latency, a bit error rate, and a packet error rate.