CIoT NAS Connection Recovery from Fallback in 5G RRC Inactive

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Solution Overview

Problem

Current 5G communication systems face inefficiencies in recovery from fallback indications for CIoT devices using control plane CIoT 5GS optimization, leading to unnecessary signaling and ambiguity in NAS mode transitions due to lack of clear indications for user plane CIoT 5GS optimization.

Innovation Solution

Implementing a method where CIoT devices in 5GMM-CONNECTED mode with RRC inactive indication use a Control Plane Service Request message for recovery from fallback, and introducing a new indication for user plane CIoT 5GS optimization to differentiate between RRC inactive state and user plane optimization-related suspensions, allowing for efficient re-establishment of NAS connections and reducing ambiguity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CIoT devices use control plane CIoT 5GS optimization in 5GMM-CONNECTED mode with RRC inactive indication, then data transmission efficiency is improved, but recovery from fallback becomes inefficient and ambiguous

Engineering Contradiction:

Improvedata transmission efficiencyVSAvoidrecovery from fallback

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent introduces a new indication parameter as an intermediary element to differentiate between RRC inactive state and user plane CIoT 5GS optimization suspension. This mediator parameter enables the NAS layer to correctly identify the suspension cause and select the appropriate recovery procedure, resolving the ambiguity in fallback recovery while maintaining control plane optimization benefits.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the indication parameter at the NAS layer to include a new parameter that indicates whether the suspension is due to RRC inactive state or user plane CIoT 5GS optimization. This parameter change enables differentiated handling of suspension scenarios, allowing efficient recovery procedures for control plane optimization while maintaining RRC inactive state management.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If no clear indication is provided for user plane CIoT 5GS optimization, then device complexity is reduced, but NAS mode transition ambiguity increases

Engineering Contradiction:

Improveindication structureVSAvoidNAS mode transition clarity

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The patent segments the suspension indication into distinct types by introducing a new indication parameter that specifically identifies user plane CIoT 5GS optimization suspension. This segmentation separates the indication for RRC inactive state from user plane optimization suspension, providing clear information for NAS mode transitions without significantly increasing overall device complexity.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If fallback recovery procedure is not optimized for control plane CIoT, then procedure simplicity is maintained, but recovery efficiency decreases

Engineering Contradiction:

Improveprocedure simplicityVSAvoidrecovery efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent introduces dynamic handling of fallback recovery by enabling the NAS layer to select different recovery procedures based on the suspension cause indication. When user plane CIoT 5GS optimization suspension is detected, the system dynamically switches to the appropriate recovery procedure, improving recovery efficiency while maintaining procedural simplicity through automated selection.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20230354460A1Method and apparatus for recovery from fallback for cellular internet of things device

Publication Date: 2023.11.02 SAMSUNG ELECTRONICS CO LTD

AI summary

There is disclosed a first method for a UE, wherein the UE is in 5GMM-CONNECTED mode with RRC inactive indication. The first method comprises: establishing a PDU session for sending data over the control plane; determining that there is data to be sent in an UL NAS TRANSPORT message; in response to the determining, requesting lower layers to resume an RRC connection; and upon receiving a fallback indication from the lower layers in response to the requesting, entering 5GMM-IDLE mode. Also disclosed is a second method for a UE, wherein the UE is in 5GMM-CONNECTED mode with RRC inactive indication. The second method comprises: establishing a PDU session for sending data over the user plane; determining that there is user data to be sent over the user plane; determining that there is no pending NAS procedure; and upon receiving a fallback indication from the lower layers, in response to the determining, entering 5GMM-IDLE mode. Also disclosed is a third method for a UE, wherein the UE is in 5GMM-CONNECTED mode with RRC inactive indication. The third method comprises: in response to receiving, from lower layer, a suspend indication, determining the type of the suspend indication; and entering a NAS mode according to the determined type of the suspend indication.