Network Node Reachability Control Without Dual Connectivity

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Solution Overview

Problem

Transitioning to 5G wireless systems with Dual Connectivity (DC) is challenging under a multi-vendor environment, necessitating a method to stabilize initial coverage without relying on DC.

Innovation Solution

A network node that manages two master nodes by storing terminal contexts, deriving connection management states, and determining reachability, enabling stabilization of coverage during system transition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Dual Connectivity (DC) is adopted to stabilize initial coverage during 5G transition, then coverage stability is improved, but implementation difficulty increases due to multi-vendor environment

Engineering Contradiction:
Improvecoverage stabilityVSAvoidimplementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of Dual Connectivity (coverage stabilization) while removing the problematic multi-vendor dependency. It achieves this by introducing a network node that manages terminal contexts and connection states independently of vendor-specific DC implementations, thereby maintaining coverage stability without the implementation complexity of multi-vendor DC.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary network node that mediates between the terminal and the core network. This node manages the terminal context and connection management states, enabling coverage stabilization without requiring direct multi-vendor DC implementation. The intermediary handles the complexity centrally while presenting a simplified interface to both terminals and the core network.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If Dual Connectivity (DC) is used to achieve coverage stabilization, then initial coverage is improved, but system complexity increases

Engineering Contradiction:
Improveinitial coverageVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the connection management function into distinct components: terminal context management and connection state derivation. By separating these functions, the system achieves initial coverage stabilization without requiring complex integrated DC implementations. The segmented architecture allows each component to operate independently, reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the operational parameters from vendor-specific DC configurations to standardized connection management states (CONNECTED, IDLE, DISCONNECTED). This parameter transformation enables coverage stabilization using universal states rather than vendor-dependent configurations, thereby reducing system complexity while maintaining initial coverage reliability.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multi-vendor DC implementation is pursued, then coverage stability is achieved, but transition difficulty increases

Engineering Contradiction:
Improvecoverage stabilityVSAvoidtransition ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements a universal network node that can serve multiple vendors and deployment scenarios. The node manages terminal contexts and connection states in a vendor-agnostic manner, enabling coverage stability during 5G transition without being locked into specific vendor implementations. This universality significantly eases the transition process by providing a common platform that works across different vendor ecosystems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a simplified copy of the connection management function that replicates the essential coverage stabilization capability without the complexity of full multi-vendor DC. By copying only the necessary functional elements (terminal context storage, connection state derivation), the system achieves coverage stability while making transition much easier through reduced complexity.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4651585A1Network node and communication method
Publication Date: 2025.11.19 NTT DOCOMO INC
  • EP4651585A1 patent drawingFigure 1
  • EP4651585A1 patent drawingFigure 2
  • EP4651585A1 patent drawingFigure 3

AI summary

A network node includes: a reception unit configured to receive, from a terminal, a registration request including information indicating that two master nodes are to be used via a RAN (Radio Access Network) node; and a control unit configured to store two terminal contexts for corresponding master nodes. The control unit stores a master node identifier corresponding to the RAN node, a global RAN node identifier corresponding to the RAN node, an identifier for identifying the terminal on an NG (Next Generation) interface in the RAN node, and an identifier for identifying the terminal on an NG interface in an AMF (Access and Mobility Management Function) in a terminal context of each of the master nodes, and the control unit derives two CM (Connection management) states of the terminal based on the terminal context of each of the master nodes, and derives a state of reachability to the terminal based on the two CM states.