Buffer Status Reporting in Wireless Devices
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Solution Overview
Problem
Current HSUPA scheduling information mechanisms in 3GPP networks do not accurately account for data stored in the MAC layer segmentation entity, leading to incorrect resource allocation and potential transmission stalls due to incomplete buffer status reporting.
Innovation Solution
Modify the TEBS field to include data from both RLC and MAC-i/is segmentation entities, and introduce a new triggering criterion that considers the total MAC buffer status (TMBS) to ensure accurate resource reporting and prevent transmission stalls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the TEBS field only includes data from RLC layer and excludes MAC layer segmentation entity data, then the reporting overhead is reduced, but the buffer status reporting accuracy deteriorates
Solution Approach 1:
The patent merges the TEBS field definition to include both RLC layer data and MAC layer segmentation entity data. The modified TEBS calculation now sums data from all logical channels at RLC layer plus data from the segmentation entity, creating a comprehensive total buffer status report that eliminates information loss while maintaining efficient reporting structure
Solution Approach 2:
The patent introduces dynamic triggering mechanisms that monitor both TEBS and TMBS values. The triggering condition adapts based on whether data exists in the segmentation entity, allowing the system to dynamically adjust reporting behavior to match actual buffer conditions, thereby improving accuracy without excessive overhead
2Measurement precision
If the WTRU does not report data in the MAC layer segmentation entity, then the scheduling information size is reduced, but the resource allocation accuracy deteriorates
Solution Approach 1:
The patent combines TEBS and TMBS into a unified resource allocation view at the Node B. The Node B scheduler now has access to the complete picture of available data across both RLC and MAC layers, enabling precise resource allocation decisions that reflect the true buffer status without increasing scheduling information transmission size
Solution Approach 2:
The patent implements feedback mechanisms where the WTRU reports accurate combined buffer status (TEBS+TMBS) to the Node B, which then uses this feedback to make informed scheduling decisions. This closed-loop feedback ensures resource allocation accuracy matches actual data availability
3Productivity
If the triggering mechanism only considers TEBS > 0, then the reporting frequency is reduced, but the transmission stall risk increases
Solution Approach 1:
The patent introduces dynamic triggering conditions that activate when either TEBS > 0 or TMBS > 0. This dynamic threshold adjustment ensures reporting occurs whenever there is data available at either layer, preventing transmission stalls while avoiding unnecessary reports when both buffers are empty, thus maintaining high productivity with minimal delay
Solution Approach 2:
The patent enables preliminary reporting when data arrives in the segmentation entity before RLC processing completes. By triggering reports based on TMBS > 0 independently, the system proactively notifies the Node B of upcoming data availability, preventing transmission stalls before they occur
4Measurement precision
If the TEBS calculation excludes segmentation entity data, then the calculation complexity is reduced, but the happy bit setting accuracy deteriorates
Solution Approach 1:
The patent merges TEBS and TMBS calculations into a unified buffer status assessment for happy bit determination. The Node B now evaluates the combined total of RLC layer data and segmentation entity data when setting the happy bit, ensuring accuracy reflects the complete data availability picture while maintaining straightforward calculation logic
Solution Approach 2:
The patent modifies the happy bit triggering parameters to consider the sum of TEBS and TMBS rather than TEBS alone. This parameter change adjusts the threshold for determining whether the WTRU is 'happy' with current resources, improving accuracy while the calculation remains a simple additive operation that does not significantly increase complexity
Data Source
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AI summary
A wireless transmit/receive unit (WTRU) reports a buffer status as part of scheduling information for enhanced dedicated channel (E-DCH) transmissions. For reporting the buffer status, the WTRU calculates a total amount of data available across all logical channels for which reporting is requested by a radio resource control (RRC) entity. The total amount of data includes an amount of data that is available for transmission and retransmission at a radio link control (RLC) entity and an amount of data that is available for transmission in a medium access control for enhanced dedicated channel (MAC-i/is) segmentation entity in case that a MAC-i/is entity is configured. The WTRU sends scheduling information including a total E-DCH buffer status (TEBS) field that is set based on the total amount of data.