HARQ Buffer Data Retention During Serving Cell Change
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Solution Overview
Problem
In multi-flow HSDPA communication networks, data loss occurs during serving cell changes due to the flushing of buffered data, which is not addressed effectively in conventional systems.
Innovation Solution
The proposed solution involves maintaining data in the HARQ buffer during serving cell changes and transferring it to the new serving cell, allowing continuous transmission without data loss, by selecting the primary and secondary serving cells based on cell quality rankings and adding neighboring cells with stronger quality to the active set during mobility events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buffered data is flushed during serving cell change to clear the buffer, then the buffer is emptied and ready for new data, but data loss occurs during the transition
Solution Approach 1:
The patent identifies buffered data at the source serving cell before the serving cell change occurs, and preliminarily prepares for data transfer by maintaining this buffered data rather than flushing it. This preliminary identification and preservation of buffered data prevents data loss during the transition to the target serving cell.
Solution Approach 2:
The patent introduces an intermediary data transfer mechanism where buffered data is transferred from the source serving cell to the target serving cell through coordination between the two cells. This intermediary transfer process ensures data integrity by preventing direct buffer flushing that would cause data loss.
2Productivity
If serving cell change is performed to improve network performance and mobility, then the mobile station can connect to better cells, but data loss occurs due to buffer flushing
Solution Approach 1:
Before executing the serving cell change, the system preliminarily identifies and preserves buffered data at the source cell, preventing the conventional buffer flushing operation. This preliminary action ensures that data transmission efficiency is maintained while avoiding data loss during the mobility transition.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining buffered data throughout the serving cell change process. Instead of interrupting data flow through buffer flushing, the system continues data transmission seamlessly by transferring buffered data from source to target cell, thus maintaining productivity while preventing data loss.
3Reliability
If buffered data is maintained during serving cell change to prevent data loss, then data integrity is preserved, but system complexity increases due to coordination requirements
Solution Approach 1:
The patent introduces coordinated interaction between source and target serving cells as an intermediary mechanism to manage buffered data transfer. This coordination allows data integrity to be maintained while distributing the complexity across multiple cells rather than requiring complex buffer management at a single point.
Solution Approach 2:
The system employs self-service mechanisms where each serving cell autonomously manages its own buffered data and participates in the transfer process based on coordination signals. This self-service approach reduces overall system complexity by distributing management responsibilities rather than requiring centralized complex control.
Data Source
AI summary
A method and apparatus for wireless communication may provide for reduced data loss during mobility events in a wireless communication network capable of downlink carrier aggregation. Some aspects of the disclosure provide for maintaining data corresponding to a flow in at least one buffer at a Node B when the Node B acts as a serving cell for the same UE both before and after a serving cell change. Another aspect of the disclosure provides for transferring buffered data from a Node B that acts as a serving cell for a UE before a serving cell change, to a Node B that acts as a serving cell for the UE after the serving cell change.