Session Management Network Element Clock Source Selection

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Solution Overview

Problem

In time-sensitive networking and mobile networks, selecting an appropriate clock source for clock synchronization between access network devices and terminal devices is a challenge due to the presence of multiple clock sources.

Innovation Solution

A method and apparatus that involve a session management network element receiving a session request with network slice and data network name (DNN) information, determining corresponding clock source information, and sending it to an access network device for synchronization, allowing the access network device to synchronize with the terminal device based on the selected clock source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple clock sources are available in the mobile network, then clock synchronization flexibility increases, but clock source selection complexity increases

Engineering Contradiction:
Improveclock source selection flexibilityVSAvoidclock source selection complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The session management network element acts as an intermediary between the mobility management network element and the access network device. It receives the session request with network slice and DNN information, determines the appropriate clock source information based on these parameters, and forwards it to the access network device. This intermediary approach resolves the contradiction by centralizing the complex selection logic in one element while maintaining flexibility through parameter-based determination.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses parameter-based determination where the clock source information is selected based on changes in network slice information and DNN parameters. When these parameters change, the session management network element determines the corresponding clock source information, enabling flexible adaptation to different network conditions without increasing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If clock source information is determined by session management network element, then synchronization accuracy improves, but signaling overhead increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidsignaling overhead
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The session management network element determines the clock source information in advance during the session establishment procedure, before the access network device needs to perform clock synchronization. This preliminary determination ensures synchronization accuracy is achieved without requiring additional signaling exchanges later, as the clock source information is already available when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the clock source determination function into the existing session management network element, combining multiple functions (session management, clock source selection, and information forwarding) into a single element. This consolidation improves synchronization accuracy by centralizing control while avoiding additional signaling overhead that would result from separate determination and communication steps.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3758424B1Method for determining clock source and device
Publication Date: 2023.08.02 HUAWEI TECH CO LTD
  • EP3758424B1 patent drawingFigure 1
  • EP3758424B1 patent drawingFigure 2
  • EP3758424B1 patent drawingFigure 3

AI summary

A clock source determining method and an apparatus are provided. The method includes: A session management network element receives a session request from a mobility management network element. The session request includes information about a network slice and a DNN, and the session request is used to request to create a session. The session management network element determines clock source information corresponding to both the information about the network slice and the DNN. The session management network element sends the clock source information to an access network device. The clock source information is used by the access network device to perform clock synchronization with a terminal device. In the method, the session management network element determines, based on the received information about the network slice and the received DNN, the clock source information corresponding to both the information about the network slice and the DNN, and sends the clock source information to the access network device, and the access network device performs the clock synchronization with the terminal device based on the clock source, so that a clock source used for the clock synchronization is selected for the access network device and the terminal device.