gNB User Plane Context Management via Direct F1-U Interface
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Solution Overview
Problem
The 5G new radio (NR) standard's user plane context setup and modification procedures in gNB-CU-UP and gNB-DU are prone to delays due to information relaying through the control plane, which can hinder downlink data delivery to user equipment.
Innovation Solution
Directly transporting downlink F1-U TNL addresses and data forwarding tunneling information between gNB-DU and gNB-CU-UP via the F1-U interface, bypassing the control plane, and enhancing existing procedures to simplify bearer context setup and handover processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If information is relayed through the control plane (gNB-CU-CP) between gNB-DU and gNB-CU-UP, then control plane anchor is ensured for correct establishment of user-plane contexts, but delays occur in data delivery
Solution Approach 1:
The patent segments the gNB into three functional entities: gNB-CU-CP (control plane), gNB-CU-UP (user plane), and gNB-DU (distributed unit). This segmentation allows control plane and user plane to operate independently, enabling direct communication between gNB-DU and gNB-CU-UP for user data while gNB-CU-CP maintains control functions, thus resolving the contradiction between control reliability and data delivery speed.
Solution Approach 2:
The patent introduces F1-C interface for control plane communication and F1-U interface for user plane communication. These dedicated interfaces act as intermediaries that separate control functions from data transmission, allowing gNB-DU and gNB-CU-UP to exchange user data directly without routing through gNB-CU-CP, thereby reducing delay while maintaining control authority.
2Reliability
If multiple class-1 actions initiated by gNB-CU-CP are used for bearer context setup, then control plane anchor is maintained, but procedure complexity increases
Solution Approach 1:
The patent divides the bearer context setup into separate control plane procedures (via F1-C) and user plane procedures (via F1-U). The gNB-CU-CP initiates control plane setup, while gNB-DU and gNB-CU-UP independently establish user plane connections using pre-configured parameters, reducing the number of sequential class-1 actions required and simplifying the overall procedure.
Solution Approach 2:
The patent implements preliminary configuration of user plane parameters and tunnel endpoint identifiers during initial gNB setup. This allows gNB-DU and gNB-CU-UP to establish user plane connections more quickly by using pre-negotiated parameters rather than negotiating all parameters in real-time through multiple control plane messages, thereby reducing procedure complexity.
Data Source
AI summary
An apparatus of a next generation NodeB (gNB) comprises one or more baseband processors to interconnect a gNB Central Unit control-plane entity (gNB-CU-CP) with a gNB Central Unit user-plane entity (gNB-CU-UP) via an E1 control plane interface and a gNB Distributed Unit (gNB-DU) via an F1 control plane interface. Rather than relying on multiple class-1 procedures initiated by gNB-CU-CP toward gNB-CU-UP and gNB-DU, the one or more baseband processors are configured to establish or modify a bearer context and to communicate data transport tunneling and/or packet data convergence protocol (PDCP) preservation status information for a specific user equipment (UE), utilizing the direct F1 user plane interface between gNB-DU and gNB-CU-UP to avoid relaying delay. The gNB can include a memory to store the bearer context and data transport tunneling information.