RLC PDU Header Overhead Reduction in VoIP Systems
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Solution Overview
Problem
Conventional RLC framing in mobile communication systems for VoIP leads to inefficient use of radio resources due to unnecessary LI fields, especially when RLC SDUs are frequently transmitted without segmentation or concatenation, resulting in excessive header overhead.
Innovation Solution
A method and apparatus that utilize a pre-defined LI field to efficiently segment and reassemble RLC PDUs, eliminating unnecessary LI fields by indicating the presence of intermediate segments with a novel pre-defined value, thereby optimizing PDU size and reducing header size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RLC framing is used with LI fields to indicate start and end of RLC SDUs, then data transmission reliability is improved, but header size increases and radio resource efficiency deteriorates
Solution Approach 1:
The patent extracts and eliminates unnecessary LI fields from the RLC PDU header when the entire RLC SDU fits within the PDU without segmentation. By removing these redundant fields, the header size is reduced while maintaining reliable data transmission through alternative mechanisms like sequence numbers and segmentation indicators when needed.
Solution Approach 2:
The patent applies different header structures to different transmission scenarios: full LI fields are used only when segmentation occurs, while a simplified header structure is used when the entire SDU can be transmitted in one PDU. This local differentiation optimizes header size based on actual transmission needs rather than using a uniform structure.
2Measurement precision
If LI fields are included in all RLC PDUs for framing information, then framing accuracy is improved, but radio resource utilization deteriorates due to excessive overhead
Solution Approach 1:
The patent applies partial action by including LI fields only when necessary (i.e., when segmentation occurs), rather than excessively including them in all PDUs. This selective inclusion maintains framing accuracy for segmented transmissions while avoiding unnecessary overhead in non-segmented transmissions, thereby optimizing radio resource utilization.
3Adaptability or versatility
If RLC PDUs are segmented to match radio channel transmission requirements, then transmission adaptability is improved, but header overhead increases due to multiple LI fields
Solution Approach 1:
The patent uses segmentation to divide large RLC SDUs into smaller PDUs that match radio channel transmission requirements. However, it mitigates the header overhead by using a simplified header structure for segmented PDUs that only include necessary segmentation indicators rather than full LI fields for each segment, thereby reducing overall header complexity.
Data Source
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AI summary
A method and apparatus for enabling efficient use of radio resources by reducing an RLC PDU size in a mobile communication system supporting voice service over a packet network are provided. An RLC layer constructs an RLC PDU without inserting information indicating the start and end of an SDU or indicating the use or non-use of padding. The RLC layer sets an LI in a header (745) to indicate inclusion of an intermediate SDU segment in the data field of the RLC PDU. Therefore, the resulting decrease of overhead arising from packet transmission facilitates the efficient use of limited radio resources.