Distributed RAN Functional Split via Data Plane Decision Logic

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Solution Overview

Problem

Current 5G network architectures face challenges in supporting flexible Radio Access Network (RAN) functional splits due to stringent transport requirements, particularly in centralized RAN setups, where delays and overloads in the control plane can hinder timely adaptations to network changes, affecting the performance of data plane nodes.

Innovation Solution

The method involves distributing RAN functional split decision-making to data plane nodes, leveraging stateful flow processing and in-switch packet generation, to complement centralized SDN control, allowing for rapid and adaptive reconfiguration of network resources and resolving conflicts through timer-based or command-based approaches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If RAN functional split decision-making is centralized in SDN controller, then network resource management is simplified, but control plane delays and overloads increase

Engineering Contradiction:
Improvenetwork resource management complexityVSAvoidcontrol plane delay
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent segments the RAN functional split decision-making process by introducing distributed control logic in data plane nodes (switches, routers, base stations) while maintaining centralized SDN controller for overall coordination. This segmentation allows local nodes to autonomously detect network changes and make split decisions without waiting for centralized controller processing, thereby reducing control plane delays while maintaining manageable complexity through hierarchical architecture.

Inventive Principle:
Principle #1Segmentation

2Productivity

If more RAN functions are centralized at CU, then operational costs are reduced and capacity gains are achieved, but transport requirements become more stringent

Engineering Contradiction:
Improveoperational efficiencyVSAvoidtransport requirement compliance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic RAN functional split adjustment that allows the system to adaptively change the degree of centralization based on real-time network conditions. When transport conditions are favorable, more functions can be centralized at CU to achieve operational efficiency; when transport conditions deteriorate, functions can be dynamically distributed to data plane nodes to ensure reliable fronthaul transport. This dynamic adaptability resolves the contradiction between operational efficiency and transport requirement compliance.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If RAN functional splits are made flexible to support varying centralization, then adaptability improves, but control plane processing complexity increases

Engineering Contradiction:
ImproveRAN functional split flexibilityVSAvoidcontrol plane processing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring multiple RAN functional split options and their corresponding control logic in data plane nodes before network operation begins. When network conditions change, nodes can quickly switch between pre-configured split options without requiring complex real-time control plane processing. This approach maintains high adaptability while reducing control plane complexity during operation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3474519B1Method for in-network dynamic radio access network functional split change utilizing software defined networking with in-switch packet generation and stateful flow processing
Publication Date: 2020.08.19 NEC CORP
  • EP3474519B1 patent drawingFigure 1
  • EP3474519B1 patent drawingFigure 2
  • EP3474519B1 patent drawingFigure 3

AI summary

A method for configuring resources of a radio access network, RAN, including a radio unit includes monitoring, by a data plane node, a quality of at least one portion of a link between the radio unit and a central processing unit of the RAN; determining, by the data plane node, that the quality of the at least one portion of the link has changed relative to a previous quality of the at least one portion of the link; generating, by the data plane node according to local control logic programmed into the data plane node, a decision specifying a placement for one or more RAN functions; and transmitting, by the data plane node to one or both of the radio unit and the central processing unit, a notification including the decision specifying the placement for the one or more RAN functions.