PDU Session Network Element Selection for AMBR Control

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Solution Overview

Problem

In the transition of PDU sessions from a 5G network to a 4G network, the lack of standardized selection criteria for session management network elements leads to inconsistent control over the aggregated maximum bit rate (AMBR), as different network elements can be selected for PDU sessions with the same data network name (DNN), disrupting AMBR control.

Innovation Solution

A method and apparatus that determine a PDU session service network element by selecting a same control plane function network element and user plane function network element for PDU sessions with a shared DNN, ensuring continuity and AMBR control by using indication information and correspondence sets to maintain consistent network element selection across sessions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different session management network elements are selected for PDU sessions with the same DNN in 5G network, then session establishment flexibility is improved, but AMBR control capability deteriorates when switching to 4G network

Engineering Contradiction:

Improvesession establishment flexibilityVSAvoidAMBR control capability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments PDU sessions by DNN (Data Network Name) and assigns a dedicated session management network element to each DNN. This segmentation ensures that all sessions with the same DNN are managed by the same network element, enabling consistent AMBR control when switching to 4G network, while still allowing multiple sessions to be established under each DNN.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an indication information mechanism as an intermediary between the control plane function network element and the mobility management device. This indication information carries the DNN-to-session-management-network-element mapping relationship, enabling the mobility management device to select appropriate network elements during 5G to 4G switching, thus maintaining AMBR control capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a same session management network element is selected for all PDU sessions with the same DNN, then AMBR control is improved, but session management complexity increases

Engineering Contradiction:

ImproveAMBR control capabilityVSAvoidsession management complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a universal mapping relationship between DNN and session management network elements that can be applied across multiple PDU sessions. Instead of configuring each session individually, the same DNN-to-network-element mapping is reused for all sessions with that DNN, reducing session management complexity while maintaining AMBR control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent copies the session management network element selection from existing sessions to new sessions with the same DNN. When a PDU session is established with a given DNN, the session management network element is selected and then copied/reused for subsequent sessions with the same DNN, simplifying the selection process while ensuring consistent AMBR control.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If standardized selection criteria for session management network elements are not established, then network element selection flexibility is improved, but switching efficiency between 5G and 4G networks deteriorates

Engineering Contradiction:

Improvenetwork element selection flexibilityVSAvoidswitching efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent performs preliminary action by establishing the DNN-to-session-management-network-element mapping relationship before 5G to 4G switching occurs. The control plane function network element determines and records this mapping in advance, so that during switching, the mobility management device can quickly retrieve the appropriate network element without complex real-time decisions, thus improving switching efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the selection criterion from random or load-based selection to DNN-based deterministic selection. By using DNN as the key parameter for selecting session management network elements, the system achieves standardized selection criteria that improve switching efficiency while maintaining flexibility through the indication information mechanism.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11895715B2Method and apparatus for determining protocol data unit session service network element

Publication Date: 2024.02.06 HUAWEI TECH CO LTD

AI summary

A method and an apparatus for determining a protocol data unit (PDU) session service network element to control an aggregated maximum bit rate (AMBR), where the method includes receiving, by a control plane function network element, a request for establishing a first PDU session from a mobility management device, where the request for establishing the first PDU session includes a first data network name (DNN), determining, by the control plane function network element, that a same control plane function network element and a same user plane function network element need to be selected for a PDU session corresponding to the first DNN, and sending, by the control plane function network element, first indication information to the mobility management device, where the first indication information is used to indicate that a same control plane function network element needs to be selected for the PDU session corresponding to the first DNN.