Configured Grant HARQ Buffer Flushing for Periodic Transmissions
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Solution Overview
Problem
Existing wireless communication systems face issues with unnecessary retransmissions using configured grants, particularly in scenarios involving HARQ processes, leading to inefficiencies in handling new and retransmission of data based on quality of service requirements.
Innovation Solution
A method and apparatus for flushing the HARQ buffer at specific periodic intervals and ignoring retransmission grants associated with a specific HARQ process ID, allowing proper handling of new and retransmission of configured grants based on quality of service requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If configured grants are used for periodic transmissions, then transmission efficiency is improved, but unnecessary retransmissions occur due to HARQ buffer management issues
Solution Approach 1:
The patent applies preliminary action by flushing the HARQ buffer at specific periodic intervals before unnecessary retransmissions can occur. The MAC entity proactively clears the buffer at predetermined times based on the configured grant periodicity, preventing the accumulation of data that would otherwise trigger redundant retransmission attempts. This advance buffer management resolves the contradiction by maintaining transmission efficiency while eliminating wasteful retransmissions.
2Reliability
If HARQ processes are managed for each period, then quality of service requirements are met, but system complexity increases
Solution Approach 1:
The patent applies periodic action by implementing a rhythm-based HARQ buffer management strategy that synchronizes with the configured grant periodicity. Instead of continuously managing HARQ processes, the system performs buffer flushing at regular intervals corresponding to the grant period. This periodic approach maintains QoS requirements through structured management while reducing complexity by eliminating the need for continuous, granular control of each HARQ process.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the buffer management behavior based on the configured grant parameters. The system modifies the HARQ buffer state according to the specific periodicity and timing parameters of the configured grant, allowing flexible adaptation to different QoS requirements without requiring complex universal management mechanisms. This parameter-driven approach simplifies the system by tying buffer management directly to existing grant configurations.
3Reliability
If retransmission grants are processed for each HARQ process, then data reliability is improved, but processing overhead increases
Solution Approach 1:
The patent applies the extraction principle by removing retransmission grants from processing when the associated HARQ buffer has been flushed. Instead of universally processing every retransmission grant that arrives, the system extracts and ignores those grants whose corresponding data has already been cleared from the buffer. This selective processing maintains data reliability for active transmissions while eliminating the processing overhead associated with redundant retransmission handling.
Data Source
AI summary
A method and apparatus for periodic transmissions for a configured grant is provided. A first device operating in a wireless communication system transmits, to a second device, a media access control (MAC) protocol data unit (PDU) by using a first resource of a configured grant (CG) in a first period for which the first resource of the CG is associated with a HARQ process identifier (ID), and flushes a HARQ buffer associated with the HARQ process ID in a second period for which a second resource of the CG is associated with the HARQ process ID. Then, the first device ignores a retransmission resource associated with the HARQ process ID based on flushing the HARQ buffer.