Uplink Data Preemption Detection for HARQ Buffer Integrity
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Solution Overview
Problem
In wireless communication systems, data transmission preemption can occur, leading to uncertainties and inefficiencies in handling hybrid automatic repeat request processes, particularly when higher priority transmissions preempt lower priority transmissions, causing gNBs to be unaware of pending data in HARQ buffers.
Innovation Solution
Remote units determine data transmission preemption by not generating transport blocks for preempted uplink grants and flushing corresponding HARQ buffers, ensuring that pending data is not lost, and transmitting stored transport blocks when the grant size matches, thereby aligning with the gNB's scheduling expectations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data transmission preemption is implemented to allow higher priority transmissions to preempt lower priority transmissions, then transmission efficiency and responsiveness to high-priority data are improved, but uncertainty arises in handling hybrid automatic repeat request processes and data integrity may be compromised
Solution Approach 1:
The patent implements feedback mechanisms where the gNB informs the UE about preemption events through specific indicators in downlink control information. This feedback loop allows the UE to understand when preemption occurs and adjust its HARQ buffer management accordingly, ensuring data integrity while maintaining transmission efficiency. The feedback includes preemption indication fields that signal to the UE whether its upcoming transmission will be preempted, enabling proactive buffer management.
Solution Approach 2:
The patent applies preliminary action by having the gNB schedule and indicate preemption decisions before the actual transmission conflict occurs. The preemption indication is provided in advance in the downlink control information, allowing the UE to prepare its HARQ buffer management in advance. This preliminary notification enables the UE to flush buffers or adjust transmissions proactively, preventing data loss before it occurs.
2Duration of action of stationary object
If the UE continues to generate transport blocks for preempted uplink grants, then data transmission continuity is maintained, but data loss occurs in the HARQ buffers due to preemption
Solution Approach 1:
The preemption indication mechanism provides real-time feedback to the UE about which uplink grants will be preempted. Based on this feedback, the UE can make informed decisions about whether to generate new transport blocks or flush existing buffers, thereby maintaining transmission continuity for non-preempted data while preventing data loss in preempted scenarios.
Solution Approach 2:
The patent introduces dynamic behavior in the UE's transport block generation process. Instead of a static rule to always generate or never generate transport blocks, the UE dynamically adjusts its behavior based on the preemption indication received. When preemption is indicated, the UE flushes the buffer; when not indicated, the UE generates transport blocks normally, thus adapting to changing transmission conditions.
3Reliability
If the UE flushes the HARQ buffer upon preemption indication, then data loss is prevented for preempted transmissions, but scheduling efficiency may be reduced due to potential premature buffer clearing
Solution Approach 1:
The preemption indication serves as precise feedback that tells the UE exactly when buffer flushing is necessary. This targeted feedback mechanism prevents premature or unnecessary buffer clearing, as the UE only flushes buffers when actually indicated to do so by the gNB. This maintains data integrity while avoiding the scheduling inefficiencies that would result from blanket buffer flushing rules.
Solution Approach 2:
The patent applies local quality by having the UE selectively flush only the specific HARQ buffers associated with preempted uplink grants, rather than flushing all buffers universally. This localized approach to buffer management ensures data integrity for preempted transmissions while preserving scheduling efficiency for non-preempted transmissions, as each buffer is managed according to its specific preemption status.
Data Source
AI summary
Apparatuses, methods, and systems are disclosed for determining data transmission preemption. One method (400) includes receiving (402) a first uplink grant for a first hybrid automatic repeat request process. The method (400) includes determining (404) that a first data transmission corresponding to the first uplink grant is preempted by a second data transmission corresponding to a second uplink grant for a second hybrid automatic repeat request process. The method (400) includes, in response to determining that the first data transmission is preempted by the second data transmission: not generating (406) a transport block for the first uplink grant; and flushing a hybrid automatic repeat request buffer corresponding to the first hybrid automatic repeat request process.