Type 3 HARQ-ACK Timing Without PDSCH Scheduling
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently handling Type 3 hybrid automatic repeat request (HARQ) acknowledgments (ACK) without physical downlink shared channel (PDSCH) scheduling, leading to potential communication errors and resource wastage due to unsynchronized base stations and user equipment (UE) operations.
Innovation Solution
The method involves determining the timing for transmitting Type 3 HARQ-ACK based on the PDSCH to HARQ feedback timing indicator in the downlink control information (DCI) message, allowing the UE to transmit ACK even without scheduled PDSCH communications, thereby avoiding errors and maintaining system synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE transmits Type 3 HARQ-ACK without PDSCH scheduling, then communication efficiency is improved, but timing synchronization between base station and UE deteriorates
Solution Approach 1:
The base station pre-configures the PDSCH to HARQ feedback timing indicator in the DCI message before the actual HARQ-ACK transmission. This preliminary timing indication allows the UE to advance-prepare and determine the exact transmission time for Type 3 HARQ-ACK, ensuring synchronization is maintained even when no PDSCH is scheduled. The timing indicator acts as a pre-arranged schedule that both parties agree upon in advance.
2Measurement precision
If the UE determines transmission time using PDSCH feedback timing indicator, then timing accuracy is improved, but resource utilization deteriorates due to potential wastage
Solution Approach 1:
The system dynamically changes the interpretation of the PDSCH to HARQ feedback timing indicator parameter based on whether a PDSCH is actually scheduled. When Type 3 HARQ-ACK is transmitted without PDSCH, the same timing indicator parameter is repurposed to indicate the HARQ-ACK transmission time relative to the DCI reception time, rather than relative to a PDSCH reception time. This parameter flexibility allows accurate timing determination while avoiding unnecessary resource allocation.
3Adaptability or versatility
If Type 3 HARQ-ACK is transmitted without PDSCH scheduling, then system flexibility is improved, but communication errors increase due to unsynchronized operations
Solution Approach 1:
The base station monitors and detects the Type 3 HARQ-ACK transmission from the UE based on the timing information provided in the DCI message. This feedback mechanism ensures that the base station is aware of and synchronized with the UE's HARQ-ACK transmission, even when no PDSCH is scheduled. The continuous feedback loop between base station and UE maintains communication accuracy while preserving system flexibility.
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a UE may determine that a DCI message requests Type 3 HARQ-ACK and does not schedule a PDSCH communication; and determine, based at least in part on a PDSCH to HARQ feedback timing indicator of the DCI message, a time to transmit the Type 3 HARQACK. Numerous other aspects are provided.