Type-3 HARQ-ACK Codebook SPS Release Feedback
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G networks, face challenges in supporting reliable HARQ-ACK feedback for semi-persistent scheduling (SPS) physical downlink shared channel (PDSCH) releases, which affects the reliability of ultra-reliable and low-latency communications (URLLC) services due to the limitations of Type-3 HARQ-ACK codebooks not supporting SPS release indications.
Innovation Solution
The implementation of a system and method that enables HARQ-ACK feedback for SPS release by configuring Type-3 HARQ-ACK codebooks to include reserved bits for SPS PDSCH releases, allowing HARQ-ACK information to be accurately conveyed, and grouping HARQ processes to improve reliability, specifically for URLLC services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Type-3 HARQ-ACK codebooks are used for feedback, then signaling overhead is reduced, but support for SPS PDSCH release indications is lost
Solution Approach 1:
The HARQ-ACK codebook is segmented into different types (Type-1, Type-2, Type-3), each optimized for specific scenarios. Type-3 is used for normal feedback to reduce overhead, while Type-1 or Type-2 are used when SPS release indications need to be supported, allowing the system to switch between codebook types based on requirements
Solution Approach 2:
The system dynamically changes the codebook type parameter based on whether SPS release indications are present. When SPS PDSCH releases occur, the system switches from Type-3 to Type-1 or Type-2 codebooks, which have the capability to carry SPS release indication bits, thereby adapting the feedback mechanism to the current transmission scenario
2Reliability
If HARQ processes are grouped, then reliability for URLLC services is improved, but processing complexity increases
Solution Approach 1:
HARQ processes are segmented into different groups based on service type (e.g., URLLC group, eMBB group). This segmentation allows independent handling and prioritization of different service requirements, improving URLLC reliability by dedicating specific resources and processing paths to critical services
Solution Approach 2:
An intermediary grouping mechanism is introduced that maps HARQ processes to service types and prioritization levels. This intermediary layer manages the complexity by providing a structured approach to handling multiple HARQ processes, allowing the system to maintain high reliability for URLLC services while organizing processing in a manageable way
Data Source
AI summary
A user equipment (UE) device is disclosed. The UE device comprises a processor configured to perform operations comprising receiving a downlink control information (DCI) from a base station. In some embodiments, the DCI comprises an indication to trigger a Type-3 hybrid automatic repeat request (HARQ) acknowledgement (ACK) feedback signal. The operations further comprise generating the Type-3 HARQ ACK feedback signal, based on processing the DCI. In some embodiments, the Type-3 HARQ ACK feedback signal comprises one or more HARQ-ACK bits for semi-persistent scheduling (SPS) physical downlink shared channel (PDSCH) release(s). In some embodiments, each of the one or more HARQ-ACK bits for SPS PDSCH release(s) is adapted to include HARQ-ACK information for an SPS PDSCH release associated with the UE. Further, the operations comprise sending the Type-3 HARQ-ACK feedback signal to the base station.