MBMS Synchronization Recovery in MBSFN via Control Frame Markers

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Solution Overview

Problem

In the LTE system, when multiple contiguous synchronous data frames are missed, base stations in the MBSFN region lose synchronization, leading to disrupted MBMS service transmission, affecting user experience during service integration scenarios.

Innovation Solution

Modifying the synchronous control frame structure by adding markers (e.g., Packet Octet Counters) to track the distribution of each synchronous frame, allowing base stations to determine missing data frames and maintain synchronization without halting subsequent data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If base stations use traditional synchronous control frame structure without detailed load distribution markers, then the system structure remains simple, but base stations cannot accurately determine missing data frames when synchronization is lost, causing service disruption

Engineering Contradiction:
Improvesynchronization recovery capabilityVSAvoidcontrol frame structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The synchronous control frame pre-contains load distribution markers (Packet Octet Counters) that indicate the data load of each synchronous frame in advance. When base stations lose synchronization, these pre-configured markers enable them to quickly identify missing frames and recover without disrupting subsequent service transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Load distribution markers serve as intermediary elements between the synchronous control frame and base station decision-making. These markers carry essential information about data frame characteristics, enabling base stations to accurately determine which frames are missing and how to recover synchronization without complex analysis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If base stations stop sending all continuous MBMS data frames until next synchronous cycle when synchronization is lost, then synchronization can be maintained, but subsequent service transmission is seriously affected

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidservice transmission continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The synchronous frame sequence is segmented into individual frames with distinct load distribution markers. When synchronization is lost, base stations can identify and handle only the missing segments rather than stopping all transmission, allowing continuous service delivery while recovering synchronization for specific frames.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The load distribution markers provide feedback information about each synchronous frame's data characteristics. Base stations use this feedback to make informed decisions about which frames to retransmit or skip, enabling selective synchronization recovery that maintains service continuity rather than blanket suspension.

Inventive Principle:
Principle #23Feedback

3Loss of information

If traditional synchronous control frames are used without load distribution markers, then the control frame structure remains simple, but base stations cannot determine the number and content of RLC PDUs, affecting synchronization recovery

Engineering Contradiction:
Improvedata frame information completenessVSAvoidcontrol frame information
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The synchronous control frame is enhanced by adding load distribution markers that change and specify key parameters of each data frame (Packet Octet Counters). These parameter changes provide base stations with the necessary information to determine RLC PDU structure and content, enabling accurate synchronization recovery without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2496009B1Method, device and system for synchronizing MBMS
Publication Date: 2021.09.01 DATANG MOBILE COMM EQUIP CO LTD
  • EP2496009B1 patent drawingFigure 1
  • EP2496009B1 patent drawingFigure 2
  • EP2496009B1 patent drawingFigure 3~4

AI summary

A method, a device and a system for synchronizing a Multimedia Broadcast Multicast Service (MBMS) are provided. The method includes: receiving a synchronous control frame from a Broadcast Multicast Service Center (BM-SC) by a network side device, carrying a load condition of a data frame in a synchronous sequence within the synchronous control frame; determining the composing information of the Radio Link Control (RLC) Protocol Data Unit (PDU) according to the load condition of the data frame in a synchronous sequence by the network side device; determining the need of stopping transmitting the missed data frame according to the composing information of the RLC PDU by the network side device while the data frame missing. The method makes the base station falling synchronization in the Multicast Broadcast Single Frequency Network (MBSFN) region recover synchronization in the case of appearing losing synchronous data frames continuously; and does not influence transmitting of the subsequent MBMS service, therefore promotes the feeling of the user receiving the MBMS service in the MBSFN region effectively.