RLC Sequence Number Synchronization After Network Restart
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Solution Overview
Problem
In the MBMS service synchronization among cells of multiple network elements, a lower-layer network element that restarts is unable to determine a correct radio link control protocol sequence number, leading to a loss of RLC sequence number synchronization with other network elements.
Innovation Solution
A preset radio link control sequence number is allocated to the first protocol data unit of each data burst, ensuring that subsequent protocol data units within the same burst also receive sequential numbering, maintaining synchronization even after a network element restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lower-layer network element restarts, then the network element can recover from failures and continue operation, but the RLC sequence number synchronization with other network elements is lost
Solution Approach 1:
The patent applies preliminary action by pre-defining a preset RLC sequence number that will be allocated to the first RLC PDU after a network element restarts. This preset sequence number is determined in advance based on the total number of RLC PDUs in the data burst, ensuring that when the restart occurs, the synchronization can be immediately restored without losing the sequence number alignment with other network elements.
Solution Approach 2:
The patent uses feedback by having the lower-layer network element detect packet loss and determine the total number of RLC PDUs in the data burst. This detected information is then fed back into the sequence number allocation process, where the preset RLC sequence number is calculated based on this feedback to ensure proper synchronization after restart.
2Loss of information
If sequential RLC sequence numbers are allocated after restart, then synchronization is maintained, but radio interference may occur from adjacent cells
Solution Approach 1:
The patent prevents radio interference by preliminarily determining the preset RLC sequence number before the actual data transmission resumes after restart. By calculating and setting this preset sequence number in advance based on the total number of RLC PDUs, the system ensures that the first RLC PDU transmitted after restart will have the correct sequence number, preventing any sequence number mismatches that could cause radio interference in adjacent cells.
3Loss of information
If the first RLC PDU after restart uses a preset sequence number, then synchronization is restored immediately, but the complexity of sequence number management increases
Solution Approach 1:
The patent simplifies the sequence number management by changing the parameter allocation approach: instead of using dynamic sequential allocation that requires complex tracking and coordination, the system uses a preset RLC sequence number that is determined by a simple calculation based on the total number of RLC PDUs. This parameter change from dynamic to preset allocation reduces the management complexity while maintaining synchronization.
Data Source
AI summary
A synchronization method and system of control sequence numbers is provide to achieve radio link control sequence number synchronization between different network elements. This method includes the following steps: allocating a preset radio link control sequence number to a first radio link control protocol data unit corresponding to a first packet in a data burst and successively allocating a radio link control sequence number to subsequent radio link control protocol data units corresponding to packets of this data burst, when each designated network element in a plurality of designated network elements performing radio link control protocol process on the packets in the data burst received by said each designated network element.