HARQ-ACK Feedback Positioning via Reference Serving Cell
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Solution Overview
Problem
In multicarrier wireless communication systems, particularly in 5G NR, the existing methods for Hybrid Automatic Repeat Request (HARQ) Acknowledgment (ACK) feedback are inadequate, leading to ambiguity in the position of HARQ-ACK bits without scheduling Physical Downlink Control Channel (PDCCH) for multiple serving cells, which affects the correct reception and scheduling flexibility.
Innovation Solution
The introduction of a reference serving cell and a predefined DCI format that carries information other than PDSCH scheduling, allowing for consistent positioning of HARQ-ACK bits and dynamic adjustment of PDCCH without explicit scheduling, thereby enhancing HARQ-ACK feedback and reducing hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a same PDCCH schedules PDSCHs or PUSCHs on multiple carriers at the same time, then scheduling efficiency is improved, but HARQ-ACK feedback becomes ambiguous and complex
Solution Approach 1:
The patent segments the HARQ-ACK feedback by introducing a reference serving cell concept. When a PDCCH on one carrier schedules resources on multiple carriers, the HARQ-ACK feedback is segmented and mapped to specific positions based on the reference serving cell index. This segmentation resolves the ambiguity by clearly identifying which serving cell's HARQ-ACK corresponds to which feedback bit position.
Solution Approach 2:
The reference serving cell acts as an intermediary element that mediates between the multi-carrier scheduling and the HARQ-ACK feedback mapping. By introducing this intermediary reference cell, the system can clearly map feedback bits to specific serving cells even when multiple carriers are scheduled simultaneously, thus resolving the information loss problem.
2Reliability
If HARQ-ACK feedback is enhanced for multi-carrier scheduling, then feedback accuracy is improved, but system complexity increases
Solution Approach 1:
The system performs preliminary action by pre-configuring the reference serving cell information through higher-layer signaling before the actual scheduling occurs. This preliminary configuration allows the UE to pre-establish the mapping relationship between serving cells and HARQ-ACK feedback positions, thereby improving feedback accuracy without adding complex real-time processing requirements during scheduling.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the reference serving cell index based on the scheduling scenario. When a PDCCH schedules multiple carriers, the reference serving cell parameter is changed to indicate which serving cell's HARQ-ACK should be mapped to which feedback position, thereby achieving accurate feedback with controlled complexity through parameter management.
3Adaptability or versatility
If cross-carrier scheduling is supported, then scheduling flexibility is improved, but HARQ-ACK bit positioning becomes ambiguous
Solution Approach 1:
The patent applies dynamics by making the reference serving cell index dynamic rather than fixed. The reference serving cell can be dynamically indicated through DCI formats or higher-layer signaling based on the specific scheduling scenario. This dynamic adjustment allows the system to maintain scheduling flexibility across different carriers while ensuring precise HARQ-ACK bit positioning by adapting the reference cell to the current scheduling context.
Data Source
AI summary
The application provides a method and device in a node for wireless communications. A node receives a first information block and receives a first signaling, the first signaling corresponds to a first cell set, the first information block is used to determine the first cell set; a node transmits a first signal in a target slot, the first signal carries a first HARQ bit block, the first HARQ bit block comprises a target HARQ-ACK bit, a detection on the first signaling is used to determine a bit value of the target HARQ-ACK bit; time-domain resources occupied by the first signaling are used to determine a reference slot; the first signaling is used to determine a number of slot(s) between the reference slot and the target slot; a reference serving cell is a serving cell related to the first cell set. The present application ensures a transmission of HARQ-ACK bits.