Communication Device Fallback from NR to LTE for Service Continuity

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Solution Overview

Problem

The deployment of Next Generation Systems (NGS) for mobile communication faces issues such as discontinuous NR coverage, unsupported or untested RRC signalling options, and QoS requirements, leading to service continuity challenges, especially during handovers from NR to LTE and for multimedia services.

Innovation Solution

A method and device for establishing communication that includes fallback procedures from Next Generation Systems (NGS) to LTE, utilizing RRC redirection and handover techniques to ensure seamless multimedia service support, particularly through initial attach procedures, mobile originated and terminated calls, and fallback mechanisms to EPS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fallback from NR to LTE is not supported, then service continuity is not supported, but implementing fallback adds system complexity

Engineering Contradiction:
Improveservice continuityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary fallback mechanism that enables seamless transition between NR and LTE networks. The system uses a coordinated handover procedure where the network entity mediates the fallback process, maintaining service continuity by preserving session context and establishing proper routing during the transition from 5G NR to 4G LTE.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary actions by pre-configuring fallback parameters and establishing fallback capability before actual handover is needed. The system prepares fallback routing information and network entity configurations in advance, enabling rapid and reliable fallback execution when service continuity is required.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If frequent handovers are needed due to discontinuous NR coverage, then service continuity is maintained, but service quality deteriorates

Engineering Contradiction:
Improveservice continuityVSAvoidservice quality
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting handover thresholds and network selection criteria based on coverage conditions. The system monitors signal quality and coverage availability, changing handover parameters adaptively to minimize frequent transitions while maintaining service continuity in discontinuous NR coverage areas.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic handover management where the system continuously adapts its behavior based on real-time network conditions. The handover procedure is made flexible and context-aware, adjusting timing and triggering conditions dynamically to reduce unnecessary handovers and maintain service quality.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If unsupported or untested RRC signalling options are used, then deployment flexibility is improved, but reliability of multimedia services deteriorates

Engineering Contradiction:
Improvedeployment flexibilityVSAvoidservice reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces feedback mechanisms that monitor the performance of RRC signalling options and provide real-time information about service quality and reliability. The system uses this feedback to validate whether deployed signalling options meet reliability requirements, enabling flexible deployment while maintaining service reliability through continuous performance verification.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3307009B1Method for establishing a communication and communication device
Publication Date: 2021.11.17 NTT DOCOMO INC
  • EP3307009B1 patent drawingFigure 1
  • EP3307009B1 patent drawingFigure 2
  • EP3307009B1 patent drawingFigure 3

AI summary

According to one embodiment, a method for establishing a communication is described comprising performing, over a first mobile radio communication network, a call control protocol message exchange indicating that a communication session establishment between a first communication device and a second communication device is intended; initiating a fallback by the first communication device from the first mobile radio communication network to a second mobile radio communication network in reaction to a specific call control message of the call control protocol message exchange; performing the fallback and establishing the communication session between the first communication device and the second communication device via the second mobile radio communication network.