SMF Data Session Management During CHF Outages

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Solution Overview

Problem

In 5G cellular communication networks, session management functions (SMFs) face disruptions when the charging function (CHF) becomes unavailable due to network failures or congestion, leading to terminated data connections and unfavorable customer experiences.

Innovation Solution

The SMF continues to manage data sessions by periodically assigning unconfirmed data units during CHF outages, recording usage, and upon CHF availability, submits a charging data initial request to account for unconfirmed data usage, ensuring uninterrupted service and accurate billing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the SMF terminates the data connection when the CHF is unavailable, then the network reliability is improved by avoiding incorrect charging, but the customer experience deteriorates due to service interruption

Engineering Contradiction:
Improvenetwork reliabilityVSAvoidcustomer experience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The SMF performs preliminary actions by continuing to manage the data session and assigning data units even when the CHF is unavailable. The SMF locally tracks unconfirmed data usage and prepares to submit charging data once the CHF becomes available, thus preventing service termination while maintaining reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The SMF acts as an intermediary between the data session management and charging functions. When the CHF is unavailable, the SMF temporarily holds the charging data and uses local tracking mechanisms to bridge the gap, ensuring continuous service while maintaining accurate charging information for later submission to the CHF

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the SMF continues to manage data sessions during CHF outage, then the customer experience is improved by maintaining service, but the charging accuracy deteriorates due to unconfirmed data usage

Engineering Contradiction:
Improvecustomer experienceVSAvoidcharging accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The SMF implements feedback mechanisms by continuously monitoring data usage and tracking unconfirmed data units. When the CHF becomes available again, the SMF submits the accumulated charging data with feedback information about the outage period, ensuring accurate charging while maintaining continuous service

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The SMF performs preliminary tracking and recording of data usage during the CHF outage, preparing accurate charging information in advance. This preliminary action ensures that when the CHF becomes available, the charging data is ready and accurate, resolving the precision issue while maintaining service continuity

Inventive Principle:
Principle #10Preliminary action

3Speed

If the SMF submits charging data immediately when CHF becomes available, then the charging speed is improved, but the system complexity increases due to tracking unconfirmed data

Engineering Contradiction:
Improvecharging speedVSAvoidsystem complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The SMF performs preliminary tracking and accumulation of charging data during the outage period, so when the CHF becomes available, the data is ready for immediate submission. This preliminary preparation increases charging speed without requiring complex real-time tracking mechanisms during the outage

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The SMF uses its own local resources to track and manage unconfirmed data usage, eliminating the need for complex external systems. The SMF self-manages the charging data accumulation and preparation, reducing overall system complexity while enabling fast charging resumption

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3903450B1Data charging during charging function outages
Publication Date: 2023.11.29 T MOBILE US INC
  • EP3903450B1 patent drawingFigure 1
  • EP3903450B1 patent drawingFigure 2
  • EP3903450B1 patent drawingFigure 3

AI summary

In a 5th-Generation (5G) cellular communication network, charging customers for data usage is performed by a network function referred to as a charging function (CHF). A session management function (SMF) of the network repeatedly sends update requests to reserve additional data for a data session. If the CHF is not available and the SMF does not receive a response to an update message, the SMF continues to assign data for the data session, even though it has not received authorization to do so from the CHF. When the CHF becomes available, the SMF sends a request to start a second data session to continue the data connection that was previously supported by the original data session. This request specifies the amount of data that was used in the original data session without being confirmed by the CHF, allowing the CHF to account for this data usage.