5GMM State Management During UE Unavailability Periods

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Solution Overview

Problem

In 5GMM procedures, the undefined 5GMM state during an unavailability period poses challenges for User Equipment (UE) in managing mo-signalling and mo-data procedures without context information, leading to difficulties in handling unavailability periods.

Innovation Solution

The UE is registered in a network and chooses a substate of either a deregistered or registered state, specifically entering the DEREGISTERED.NO-CELL-AVAILABLE or 5GMM-REGISTERED.NO-CELL-AVAILABLE substate upon activation of the unavailability period, initiating only deactivation procedures and cell/PLMN reselection, and eventually deactivating the unavailability period through initial registration or mobile registration updates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE stores its 5GMM and 5GSM context in USIM or non-volatile memory during unavailability period, then the UE can reuse the context later after the unavailability period, but the 5GMM state becomes undefined and the UE cannot handle mo-signalling, mo-data and NAS registration procedure

Engineering Contradiction:

Improvecontext reuse capabilityVSAvoidsignaling handling capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention segments the deregistered state into two distinct substates: DEREGISTERED.NORMAL-SERVICE and DEREGISTERED.NO-CELL-AVAILABLE. This segmentation allows the UE to selectively enter different substates based on whether a cell is available, thereby resolving the contradiction between maintaining context for future reuse and preserving the ability to handle signaling procedures. When a cell is available, the UE enters DEREGISTERED.NORMAL-SERVICE and can handle signaling; when no cell is available, the UE enters DEREGISTERED.NO-CELL-AVAILABLE and stores context for later reuse.

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If the UE enters a deregistered state during unavailability period, then the UE can store context for later reuse, but the UE loses the ability to perform registration procedures and mobility management

Engineering Contradiction:

Improvestored context informationVSAvoidprocedure execution capability

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The invention introduces dynamic state transitions that allow the UE to adapt its behavior based on radio conditions. The UE can transition between DEREGISTERED.NORMAL-SERVICE and DEREGISTERED.NO-CELL-AVAILABLE substates, and can also transition back to registered states when appropriate. This dynamic adaptability resolves the contradiction by allowing the UE to store context when needed while retaining the capability to perform procedures when conditions permit.

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If the UE remains in a registered state during unavailability period, then the UE can handle signaling procedures, but the stored context may be lost or become invalid

Engineering Contradiction:

Improvesignaling handling capabilityVSAvoidcontext validity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention applies preliminary action by having the UE proactively transition to the DEREGISTERED.NO-CELL-AVAILABLE substate and store its 5GMM and 5GSM context in USIM or non-volatile memory before the unavailability period fully sets in. This preliminary storage of context ensures that when the UE becomes unavailable, its context is preserved and will remain valid for future reuse, thereby resolving the contradiction between handling signaling and maintaining context validity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240334368A1Handling 5GMM state after activation of unavailability period

Publication Date: 2024.10.03 MEDIATEK SINGAPORE PTE LTD

AI summary

A method for managing an unavailability period performed by a user equipment (UE) is provided. The method comprises being registered in a network and choosing a substate of a deregistered state when an unavailability period is activated by the UE using a deregistration procedure or choosing a substate of a registered state when an unavailability period is activated by the UE using a registration procedure.