HARQ-ACK Feedback Timing for Multi-PDSCH Low-Latency Scheduling
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Solution Overview
Problem
Existing 5G communication systems face challenges in efficiently managing HARQ-ACK feedback timing for multiple PDSCHs, particularly in scenarios with variable sub-carrier spacing, leading to increased downlink control information overhead and latency issues.
Innovation Solution
A method is introduced for flexible HARQ-ACK feedback by dynamically indicating feedback delay based on service requirements and user capabilities, allowing for variable HARQ-ACK delays in both FDD and TDD systems, and enabling HARQ-ACK feedback in subslots for reduced latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed HARQ-ACK feedback timing is used for multiple PDSCHs, then scheduling is simplified, but downlink control information overhead increases and latency increases
Solution Approach 1:
The patent introduces dynamic HARQ-ACK feedback timing where the feedback delay can be flexibly adjusted based on service requirements and UE capabilities. The network can indicate different K1 values (feedback delay parameters) through DCI signaling, allowing the system to transition from fixed to dynamic timing adaptation. This resolves the contradiction by enabling variable feedback timing that reduces control overhead while maintaining scheduling manageability through standardized procedures.
Solution Approach 2:
The patent changes the HARQ-ACK feedback timing parameter (K1) from a fixed value to a dynamically adjustable parameter. By allowing K1 to vary based on service type (eMBB, URLLC, mMTC), UE capabilities, and network conditions, the system can optimize control overhead and latency without sacrificing scheduling simplicity. The standardized mechanisms for indicating and managing variable K1 values maintain ease of operation while achieving parameter flexibility.
2Device complexity
If standard slot-based HARQ-ACK feedback is used, then timing is simplified, but latency is increased
Solution Approach 1:
The patent segments the traditional slot-based feedback mechanism into subslot-level feedback opportunities. By allowing HARQ-ACK feedback to be transmitted at subslot boundaries rather than waiting for the next full slot, the system reduces feedback latency while maintaining timing management through standardized subslot definitions and signaling procedures. This segmentation enables faster feedback without requiring complete redesign of the timing structure.
Solution Approach 2:
The patent enables dynamic selection of feedback timing opportunities within slots, allowing the system to adapt between slot-based and subslot-based feedback based on latency requirements. For URLLC services, subslot feedback can be triggered to reduce latency, while eMBB services can use standard slot-based feedback. This dynamic approach balances timing management complexity with latency reduction across different service types.
3Adaptability or versatility
If variable HARQ-ACK delays are implemented, then system adaptability improves, but device complexity increases
Solution Approach 1:
The patent implements a universal HARQ-ACK feedback mechanism that can handle multiple service types (eMBB, URLLC, mMTC) and timing requirements through a unified framework. The same DCI signaling structures and standardized procedures are used to indicate variable K1 values and subslot feedback opportunities across different service types, rather than requiring separate mechanisms for each service. This multi-functionality achieves adaptability while controlling device complexity through standardized universal procedures.
Solution Approach 2:
The patent incorporates UE capability feedback mechanisms where UEs report their supported HARQ-ACK feedback timing capabilities to the network. The network uses this feedback to appropriately configure variable K1 values and subslot feedback opportunities matched to UE capabilities, avoiding configurations that would exceed UE processing capabilities. This feedback loop enables adaptability while preventing device complexity from becoming unmanageable by aligning configurations with actual UE capabilities.
Data Source
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AI summary
The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. An apparatus in a wireless communication system and a method performed by the same are provided, with the method including receiving a physical downlink control channel (PDCCH), receiving a physical downlink shared channel (PDSCH) based on the received PDCCH, and performing hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback for the received PDSCH.