EPS Fallback Procedure Selection for Wireless Devices

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Solution Overview

Problem

Current communication systems face challenges in efficiently handling EPS Fallback scenarios, particularly in the absence of an N26 interface between 5G and E-UTRAN networks, which complicates the handover process and requires additional signaling steps.

Innovation Solution

The method involves a wireless device receiving a redirection instruction to switch from a first network to a second network, selecting a procedure based on the availability of the N26 interface, and performing either a Tracking Area Update (TAU) or an attach request to establish communication, depending on interface support, thereby optimizing signaling and handover processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If EPS Fallback is performed without N26 interface support, then handover can be achieved between 5G and E-UTRAN networks, but additional signaling steps are required complicating the handover process

Engineering Contradiction:
Improvehandover capabilityVSAvoidsignaling process
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic procedure selection based on N26 interface availability. The wireless device and network dynamically adapt between TAU-based and attach request-based fallback procedures depending on whether the N26 interface is present, optimizing the handover process for each specific network configuration scenario.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the procedural parameters of the handover process based on interface availability. When N26 is unavailable, the system transitions from using existing context information to performing full attach procedures, fundamentally changing the handover parameter set to accommodate the missing interface.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If N26 interface is unavailable between 5G and E-UTRAN, then direct handover is simplified, but interface availability complicates the handover process

Engineering Contradiction:
Improvehandover efficiencyVSAvoidinterface compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary decision-making mechanism that determines the appropriate fallback procedure based on N26 interface availability. This intermediary layer (the conditional logic selecting between TAU and attach procedures) mediates between the simplified direct handover and the need for interface compatibility, choosing the optimal path based on network conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the handover process into two distinct procedural paths: one for when N26 interface is available (using TAU procedure) and another for when it is unavailable (using attach request procedure). This segmentation allows each path to be optimized independently for its specific interface configuration.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If redirection instruction is sent without considering interface availability, then handover can be initiated, but signaling overhead increases

Engineering Contradiction:
Improvehandover initiationVSAvoidsignaling overhead
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent performs preliminary assessment of N26 interface availability before initiating the EPS Fallback procedure. By determining interface support in advance, the system can select the appropriate procedure (TAU or attach request) beforehand, avoiding unnecessary signaling steps and reducing overall signaling overhead during the actual handover execution.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4057695B1Communication establishment
Publication Date: 2023.08.30 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4057695B1 patent drawingFigure 1
  • EP4057695B1 patent drawingFigure 2~3
  • EP4057695B1 patent drawingFigure 4

AI summary

In an example aspect, a method performed by wireless device for communication establishment is provided. The method comprises, in response to a request for establishment of a communication with the wireless device using a first network, receiving a redirection instruction to redirect to a second network, and in response to whether a node in the second network supports communication with a node in the first network, selecting a first procedure or a second procedure for establishing the communication using the second network.