UE HARQ-ACK Feedback with Sub-Slot PUCCH Collision Handling
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Solution Overview
Problem
The 3GPP standards face challenges in efficiently managing Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) feedback for diverse service types in 5G networks, particularly in handling multiple PUCCH transmissions within a slot, addressing issues such as HARQ-ACK multiplexing, resource allocation, and collision handling for Ultra-Reliable and Low-Latency Communications (URLLC) and Enhanced Mobile Broadband (eMBB) services.
Innovation Solution
The method involves constructing at least two HARQ-ACK codebooks for different service types, using semi-static and dynamic codebooks to manage HARQ-ACK feedback, and employing sub-slot level timing indications for PUCCH resources, along with collision handling rules to prioritize URLLC transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PUCCH transmissions are allowed within a slot for diverse service types, then the system can support both URLLC and eMBB services simultaneously, but resource allocation complexity and collision handling difficulty increase
Solution Approach 1:
The patent segments the HARQ-ACK feedback mechanism by constructing separate codebooks for different service types (URLLC and eMBB). This segmentation allows independent management of feedback resources for each service type, reducing the complexity of allocating resources across diverse services while maintaining support for multiple service types simultaneously.
Solution Approach 2:
The patent introduces a service type identifier as an intermediary element that enables the network to distinguish between URLLC and eMBB transmissions. This intermediary allows the receiver to apply different collision handling rules and resource allocation strategies based on the service type, simplifying the overall resource management while supporting diverse services.
2Loss of time
If sub-slot level timing indications are used for PUCCH resources, then latency is reduced for URLLC services, but the complexity of timing synchronization and resource management increases
Solution Approach 1:
The patent implements dynamic timing indications at the sub-slot level for PUCCH resources, allowing the timing to be flexibly adjusted based on service type and channel conditions. This dynamic approach reduces latency for time-critical URLLC services while maintaining compatibility with standard slot-based timing for eMBB services, managing complexity through conditional applicability.
Solution Approach 2:
The patent applies sub-slot level timing precision locally only to URLLC services where low latency is critical, while maintaining standard slot-based timing for eMBB services. This localized application of enhanced timing precision reduces the overall system complexity while achieving the latency reduction benefit where most needed.
3Reliability
If separate HARQ-ACK codebooks are constructed for different service types, then feedback reliability is improved, but the overhead and processing complexity increase
Solution Approach 1:
The patent segments the HARQ-ACK feedback into separate codebooks for URLLC and eMBB services. This segmentation improves reliability by ensuring that critical URLLC acknowledgments are transmitted independently without being affected by eMBB traffic variations. The overhead is managed through efficient codebook construction that includes only necessary acknowledgment bits for each service type.
Solution Approach 2:
The patent changes the parameter of codebook structure based on service type, using different codebook formats and sizes optimized for each service. This allows the system to maintain high reliability for URLLC with compact codebooks while efficiently managing overall overhead through service-specific parameter optimization.
4Reliability
If collision handling rules prioritize URLLC transmissions, then URLLC reliability is improved, but eMBB service quality may be degraded
Solution Approach 1:
The patent implements preliminary anti-action by pre-defining collision handling rules that prioritize URLLC transmissions before collisions occur. These rules are established through service type identification and codebook separation, allowing the system to automatically apply appropriate prioritization without real-time decision-making, thus ensuring URLLC reliability while maintaining fair resource distribution for eMBB services through structured resource allocation.
Data Source
AI summary
A communication system is disclosed in which a user equipment (UE) receives downlink control information (DCI) in accordance with at least one of a first DCI format and a second DCI format, the DCI indicating at least one communication resource to be used for transmitting Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) feedback for downlink data at a symbol or sub-slot level, and the DCI format used indicating whether a timing window in which said downlink data is to be transmitted is shorter or longer than a slot length. The UE receives downlink data during said timing window and transmits corresponding HARQ-ACK using the indicated at least one communication resource.