HARQ-ACK Codebook Segmentation for Unicast Multicast Overlap
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Solution Overview
Problem
In 5G wireless communication systems, the simultaneous reception of unicast and multicast/groupcast traffic in a single slot leads to overlapping Physical Downlink Shared Channels (PDSCHs), causing conflicts in HARQ-ACK codebooks, which requires a redesign of uplink feedback mechanisms to ensure accurate and conflict-free HARQ-ACK determination.
Innovation Solution
The method involves configuring multiple candidate indexes for each serving cell to determine the position of HARQ-ACK bits based on the type of PDSCH, ensuring that HARQ-ACKs for overlapping PDSCHs used in unicast and multicast/groupcast transmissions do not conflict, and using properties like RNTI and traffic type to select appropriate indexes for HARQ-ACK determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a terminal receives multiple PDSCHs occupying overlapping time-domain resources simultaneously in a slot, then the terminal can receive unicast and multicast/groupcast traffics at the same time, but conflicts occur in HARQ-ACK codebook determination
Solution Approach 1:
The patent segments the HARQ-ACK codebook into multiple codebooks, with each codebook corresponding to a specific PDSCH type (unicast or multicast/groupcast). This segmentation allows independent determination of HARQ-ACK bits for each PDSCH type, eliminating conflicts that arise when multiple PDSCHs with overlapping time-domain resources are received simultaneously. The segmentation principle directly resolves the contradiction by maintaining reliability through separate codebook structures while preserving the adaptability to handle multiple traffic types concurrently.
2Device complexity
If a unified HARQ-ACK codebook is used for both unicast and multicast/groupcast PDSCHs, then the feedback mechanism is simple, but conflicts arise when determining HARQ-ACK positions for overlapping PDSCHs
Solution Approach 1:
The patent divides the unified HARQ-ACK codebook into multiple segmented codebooks based on PDSCH types. Each segmented codebook maintains a simplified structure for its specific PDSCH type, while the overall system achieves reliability through the segmented architecture. This approach balances complexity and reliability by avoiding the need for a completely new feedback mechanism while resolving position determination conflicts through segmentation.
Solution Approach 2:
The patent applies different codebook determination rules locally to different PDSCH types. Unicast PDSCHs use one set of rules for HARQ-ACK position determination, while multicast/groupcast PDSCHs use another set of rules. This local quality approach allows each PDSCH type to have optimized determination rules suited to its characteristics, preventing conflicts while maintaining overall system efficiency.
3Adaptability or versatility
If multiple candidate indexes are configured for each serving cell, then HARQ-ACK position determination becomes more flexible, but the configuration complexity increases
Solution Approach 1:
The patent introduces multiple candidate indexes as configurable parameters for HARQ-ACK position determination. These parameters allow flexible adaptation to different PDSCH types and scenarios. The configuration complexity is managed by providing default values and standardized configuration procedures, allowing the system to achieve high adaptability without excessive complexity in practical deployment.
Data Source
AI summary
A method and a device in nodes used for wireless communication are disclosed by the present disclosure. The node receives a first signaling and a first signal; and then transmits a first bit block in a first time-frequency resource set; the first signaling is used to determine time-frequency resources occupied by the first signal, the first bit block comprises a first information block, which is used to indicate whether the first signal is correctly received; the first signaling is used to determine the first time-frequency resource set; a target index is equal to one of the K1 candidate indexes, and is used to determine a position of the first information block in the first bit block. The present disclosure optimizes the system performance by improving the method and device for feedback information transmission in multicast/groupcast mode.