One-Shot HARQ-ACK Feedback for Smaller URLLC Codebooks
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently configuring hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback, particularly in ultra-reliable low-latency communication (URLLC), which results in large HARQ-ACK codebooks and impacts performance due to increased latency and reduced reliability, especially on unlicensed frequency carriers.
Innovation Solution
Configuring one-shot HARQ-ACK feedback modes by receiving RRC parameters, MAC control elements, and DCI to trigger HARQ-ACK codebooks, and selectively reporting HARQ-ACK information based on activated serving cells, priority, and timing conditions to reduce codebook size and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional HARQ-ACK feedback configuration is used to ensure comprehensive coverage of all HARQ processes, then reliability is improved, but the HARQ-ACK codebook size increases causing increased latency and reduced performance
Solution Approach 1:
The patent extracts only the necessary HARQ-ACK information from the complete codebook by identifying and reporting only those HARQ processes that require feedback based on PDSCH reception status. This selective extraction reduces the codebook size while maintaining reliability for processes that actually need acknowledgment.
Solution Approach 2:
Instead of providing feedback for all HARQ processes (excessive action), the patent applies partial action by providing feedback only for the subset of HARQ processes that have received PDSCH transmissions. This reduces overhead while ensuring sufficient reliability for active processes.
2Reliability
If HARQ-ACK codebook includes all configured HARQ processes to ensure complete feedback coverage, then reliability is improved, but the codebook becomes large impacting system performance
Solution Approach 1:
The patent extracts only the essential HARQ-ACK bits corresponding to actually received PDSCH transmissions, removing unnecessary feedback elements for inactive HARQ processes. This extraction maintains feedback completeness for active processes while reducing overall codebook size to improve system performance.
Solution Approach 2:
The patent dynamically changes the HARQ-ACK codebook parameters (size, content) based on the actual PDSCH reception status and HARQ process states. This adaptive parameter adjustment ensures completeness when needed while optimizing performance when fewer processes are active.
3Ease of operation
If one-shot HARQ-ACK feedback is triggered for all serving cells to simplify configuration, then ease of operation is improved, but the feedback payload size increases reducing efficiency
Solution Approach 1:
The patent extracts feedback information only for activated serving cells that have actual PDSCH transmissions, removing unnecessary feedback for non-activated cells. This maintains configuration simplicity while reducing the payload size to improve transmission efficiency.
Solution Approach 2:
Instead of providing one-shot feedback for all serving cells (excessive action), the patent applies partial action by providing feedback only for the subset of activated serving cells with pending HARQ processes, reducing payload size while maintaining operational simplicity.
Data Source
AI summary
The present disclosure describes methods, system, and devices for configuring hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback for physical downlink shared channel (PDSCH) transmission. The method includes receiving, by a user equipment (UE), a radio resource control (RRC) parameter to configure a one-shot HARQ-ACK feedback mode; receiving, by the UE, a medium access control (MAC) control element (CE) indicating a list of activated serving cells; receiving, by the UE, a downlink control information (DCI) comprising an one-shot request field with a positive value, the DCI triggering a one-shot HARQ-ACK codebook; and transmitting, by the UE, a one-shot HARQ-ACK feedback for the list of activated serving cells.