Session Management for Per-Stream TSN Assistance in 5G Timing

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Solution Overview

Problem

Existing 5G systems struggle to apply TSC assistance information (TSCAI) to specific TSN streams accurately due to drift differences between TSN and 5G time domains, leading to inefficient scheduling and unsynchronized TSN time synchronization across multiple TSN streams.

Innovation Solution

Implementing a configuration that sets TSCAI for each QoS flow and TSN stream, incorporating identification information and accounting for the difference in the rate of progress between TSN and 5G times, allowing precise application of TSCAI to specific TSN streams through network nodes like SMF, UPF, and RAN.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If TSCAI is applied to multiple TSN streams to improve time synchronization coverage, then more TSN streams benefit from synchronized control, but it becomes difficult to apply TSCAI accurately to specific individual streams

Engineering Contradiction:

ImproveTSCAI application coverageVSAvoidTSCAI application accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments TSCAI configuration by introducing stream identification information (such as VLAN ID or stream ID) to distinguish different TSN streams. This allows TSCAI to be applied to specific individual streams rather than all streams collectively, resolving the contradiction between broad coverage and precise application by enabling granular per-stream configuration while maintaining multi-stream support.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If TSCAI parameters are modified to correct drift difference between TSN time and 5G time, then time synchronization accuracy improves, but the complexity of time domain management increases

Engineering Contradiction:

Improvetime synchronization accuracyVSAvoidtime domain management complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary function in the SMF that manages time domain information and coordinates TSCAI parameter modifications. This intermediary layer handles the complexity of drift correction between TSN and 5G time domains, isolating the time synchronization complexity from individual TSN stream processing and simplifying overall system management while maintaining high synchronization accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If TSCAI is configured for each TSN stream to enable precise scheduling, then scheduling accuracy improves, but the configuration and management overhead increases

Engineering Contradiction:

Improvescheduling accuracyVSAvoidconfiguration overhead

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a universal TSCAI configuration mechanism that uses common parameters (such as periodicity and burst arrival time) applicable across multiple TSN streams. By defining stream identification information that can reference these universal parameters, the system achieves precise per-stream scheduling while reducing configuration overhead through parameter reuse and centralized management in the SMF.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4037244B1Session management device, user plane device, and access movement management device

Publication Date: 2025.12.03 NTT DOCOMO INC

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AI summary

A session management apparatus including: a reception unit configured to receive, from a user plane apparatus, time comparison information between a TSN time of a TSN time domain and a 5G time, and identification information of the TSN time domain; and a transmission unit configured to transmit, to a base station apparatus, TSN assistance information determined based on the time comparison information and identification information of a TSN stream for each of one or more TSN streams that belong to the TSN time domain.