RLC Sequence Number Synchronization for MBMS Data Recovery

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Solution Overview

Problem

In the MBMS service synchronization among multiple network elements, lower layer network elements that have restarted or lost data packets struggle to maintain RLC sequence number synchronization, leading to radio interference among adjacent cells.

Innovation Solution

A method where a first network element sends a request to a second network element to acquire the RLC sequence number for data packets, allowing the allocation of the correct sequence number to RLC PDUs, ensuring synchronization among lower layer network elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If lower layer network elements independently process MBMS data packets after restart or data loss, then processing autonomy is improved, but RLC sequence number synchronization deteriorates

Engineering Contradiction:
Improveprocessing autonomyVSAvoidRLC sequence number synchronization
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the first network element queries the second network element for the correct RLC sequence number based on received data packets. The second network element returns the accurate sequence number information, which the first network element uses to synchronize its RLC processing. This feedback loop ensures that even when network elements independently process data after restart or loss, they maintain sequence number synchronization through periodic correction queries.

Inventive Principle:
Principle #23Feedback

2Reliability

If RLC sequence number synchronization is maintained through continuous monitoring and correction, then synchronization reliability is improved, but network signaling overhead increases

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidnetwork signaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent employs periodic action by having the first network element query the second network element for RLC sequence number information at specific intervals or trigger events (such as after restart or data packet loss). Rather than continuous monitoring, the system performs synchronization checks periodically or event-driven, reducing unnecessary signaling while maintaining synchronization reliability when needed.

Inventive Principle:
Principle #19Periodic action

3Speed

If lower layer network elements autonomously allocate RLC sequence numbers, then processing speed is improved, but sequence number consistency across cells deteriorates

Engineering Contradiction:
Improveprocessing speedVSAvoidsequence number consistency
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies preliminary action by having the second network element pre-calculate and maintain the correct RLC sequence number information ready for query. When the first network element needs synchronization, it can quickly obtain the pre-prepared sequence number information without requiring complex real-time coordination, thus maintaining both processing speed and sequence number consistency.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2320599B1Method and apparatus for recovery processing of synchronously transmitted service data
Publication Date: 2015.10.21 ZTE CORP
  • EP2320599B1 patent drawingFigure 1
  • EP2320599B1 patent drawingFigure 2
  • EP2320599B1 patent drawingFigure 3

AI summary

A method and apparatus for recovering synchronization among transmitted service data are disclosed in the present invention. The method comprises: a first network element sending a request to a second network element, the request carrying first information and identification information of data stream, wherein, the request is used to acquire a Radio Link Control sequence number of a Radio Link Control protocol data unit corresponding to the data packet indicated by the first information in the data stream; the first network element receiving second information returned by the second network element according to the request and allocating the Radio Link control sequence number carried in the second information to the Radio Link Control protocol data unit in the first network element. With the present invention, the RLC sequence number synchronization among the lower layer network elements can be maintained by acquiring by the lower layer network elements which have lost data or which have restarted the right Radio Link Control (RLC) sequence number from other lower layer network elements which work properly, thus avoid radio interference among the adjacent cells.