UE PDN Connectivity Retry via Cause Code Parameter Adjustment

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Solution Overview

Problem

In LTE wireless communication networks, certain cause codes lead to permanent rejection of PDN connectivity requests without a retry mechanism, resulting in permanent data service denial due to user errors or unawareness, such as incorrect PDN types or APN combinations.

Innovation Solution

User equipment automatically alters rejected parameters like PDN type or APN based on specific cause codes and retries the PDN connectivity request, enabling reestablishment of EPS bearers without user interaction, thereby avoiding permanent rejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the network rejects PDN connectivity requests with specific cause codes, then network control and policy enforcement are improved, but user service continuity deteriorates due to permanent rejection without retry mechanism

Engineering Contradiction:

Improvenetwork controlVSAvoidservice continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The UE automatically detects cause codes in rejection messages and self-corrects its PDN connectivity requests by modifying parameters such as APN, PDN type, or RAT based on the received cause code, enabling autonomous retry without network intervention or user action

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The UE uses the cause code feedback from the network rejection message to determine what parameter to change in the subsequent PDN connectivity request, creating a closed-loop control system that adapts to network policies

Inventive Principle:

Principle #23Feedback

2Reliability

If the UE is required to manually switch off or remove USIM to retry PDN connectivity, then network security and policy compliance are improved, but user convenience and service recovery deteriorate

Engineering Contradiction:

Improvepolicy complianceVSAvoiduser convenience

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The UE autonomously handles the retry process by automatically interpreting cause codes and modifying its own PDN connectivity parameters, eliminating the need for user actions such as switching off the device or removing the USIM card

Inventive Principle:

Principle #25Self-service

3Productivity

If the UE automatically alters parameters based on cause codes, then service recovery is improved, but device complexity increases due to additional processing logic

Engineering Contradiction:

Improveservice recoveryVSAvoidprocessing logic

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The UE changes specific parameters (APN, PDN type, RAT) in its PDN connectivity request based on the cause code received, allowing service recovery through parameter adjustment rather than complex procedural changes

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9980310B2Method for processing unsuccessful PDN establishment request

Publication Date: 2018.05.22 MEDIATEK INC

AI summary

A method of enhanced session management procedure is proposed. A user equipment, upon receiving a rejected PDN connectivity request with a cause code, automatically alters the rejected factor to fit network restrictions based on the received cause code. The UE then retries the PDN connectivity procedure by sending a subsequent PDN connectivity request using the altered factor. By automatically altering the rejected factor and reattempting to establish an EPS bearer for data service without user interaction, possible permanent rejection can be avoided in case of user error or unawareness.