HARQ Buffer Flushing for Deprioritized Uplink Grants
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Solution Overview
Problem
In New Radio (NR) wireless communication systems, there is no specified Hybrid Automatic Repeat Request (HARQ) process for deprioritized uplink grants, leading to inefficiencies in data transmission and resource management.
Innovation Solution
A method for a user equipment (UE) to perform a HARQ process for a deprioritized uplink grant by receiving overlapping UL grants, determining prioritization, and flushing the HARQ buffer upon receiving a retransmission grant, allowing for efficient retransmission of data on a new resource.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple overlapped UL grants are scheduled to reduce data transmission delay, then data scheduling delay is reduced, but there is no specified HARQ process for deprioritized UL grants leading to inefficiency
Solution Approach 1:
The patent applies parameter changes by modifying the HARQ buffer state based on the grant priority status. When a deprioritized UL grant is identified, the system changes the HARQ buffer state to flushed state, effectively managing the HARQ process differently based on the grant's priority level. This resolves the contradiction by enabling proper HARQ processing for deprioritized grants while maintaining the benefit of overlapped grants for reducing transmission delay.
2Ease of operation
If a prioritization procedure is performed between overlapped PUSCHs, then one PUSCH is selected for transmission, but the deprioritized PUSCH cannot be transmitted without a specified HARQ process
Solution Approach 1:
The patent extracts the HARQ buffer flushing operation as a separate, explicit action for deprioritized UL grants. By taking out the HARQ buffer flush as a distinct step in the prioritization process, the system ensures that deprioritized grants are properly handled through HARQ retransmission mechanisms, thereby completing the HARQ process for all grants regardless of priority status.
3Device complexity
If no HARQ buffer flush is performed for deprioritized grants, then the HARQ buffer remains occupied, but retransmission cannot be properly handled
Solution Approach 1:
The patent applies preliminary action by flushing the HARQ buffer in advance when a deprioritized UL grant is identified. This preliminary flush action prepares the system for subsequent retransmission operations, ensuring that the HARQ buffer is in the correct state to receive and process retransmission data. This resolves the contradiction by enabling proper retransmission handling while maintaining clear HARQ buffer management through the preliminary flush operation.
Data Source
AI summary
A method for a UE performing a Hybrid Automatic Repeat Request (HARQ) process for a deprioritized uplink (UL) grant is disclosed. The method comprises receiving, a first UL grant scheduling a first UL transmission on a first UL resource and a second UL grant scheduling a second UL transmission on a second UL resource, the second UL resource at least partially overlapping the first UL resource in a time domain, determining the first UL grant as a prioritized UL grant, determining the second UL grant as a deprioritized UL grant, performing the first UL transmission scheduled by the prioritized UL grant, receiving a third UL grant scheduling a retransmission on a third UL resource, the retransmission corresponding to the second UL transmission scheduled by the deprioritized UL grant and flushing a HARQ buffer of a HARQ process for the second UL transmission in response to receiving the third UL grant.