HARQ-ACK Codebook Bits Across Active UL BWP Changes
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Solution Overview
Problem
The introduction of PUCCH carrier switching in wireless communication systems complicates the generation of Type-1 HARQ-ACK codebooks, particularly during active BWP changes, leading to issues with HARQ-ACK information bit determination and potential impacts on scheduling flexibility and reliability.
Innovation Solution
A method for determining HARQ-ACK codebooks that considers active BWP changes by defining target serving cells and time units, ensuring flexible scheduling and reducing the impact of BWP changes on HARQ-ACK generation, while maintaining reliability and overhead optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PUCCH carrier switching functionality is introduced to support URLLC low latency requirements, then system adaptability and scheduling flexibility are improved, but HARQ-ACK codebook generation complexity increases and reliability may be compromised during active BWP changes
Solution Approach 1:
The patent segments the HARQ-ACK codebook generation process by introducing a target serving cell concept that separates the PUCCH transmission cell from the serving cell experiencing BWP changes. This segmentation allows independent handling of codebook generation on the first serving cell while determining PUCCH transmission on the target serving cell, thereby reducing generation complexity while maintaining adaptability.
Solution Approach 2:
The target serving cell acts as an intermediary between the source serving cell (where BWP changes occur) and the PUCCH transmission. By introducing this intermediary layer, the patent enables indirect HARQ-ACK feedback transmission that avoids the complexity and potential reliability issues of direct transmission during active BWP changes, while still supporting carrier switching functionality.
2Reliability
If HARQ-ACK information bits are transmitted for all serving cells during active BWP changes, then feedback reliability is improved, but feedback overhead and system complexity increase
Solution Approach 1:
The patent applies local quality by making the HARQ-ACK codebook generation cell-specific rather than system-wide. The target serving cell determines whether to generate HARQ-ACK information bits for the first serving cell based on local conditions (whether it is the target serving cell), thereby reducing unnecessary feedback overhead while maintaining reliability where needed.
Solution Approach 2:
Instead of transmitting HARQ-ACK information for all serving cells unconditionally, the patent implements partial action by only generating HARQ-ACK bits when the target serving cell condition is met. This selective approach reduces feedback overhead while maintaining sufficient reliability for the critical URLLC communications.
Data Source
AI summary
The present disclosure provides a method and a device in a node used for wireless communications. A first receiver receives a first signaling, the first signaling being used to determine a target serving cell and a first time unit, where the target serving cell is either a first serving cell or a second serving cell; a first transmitter determines a first HARQ-ACK codebook and transmits a first signal in the first time unit on the target serving cell, the first signal carrying the first HARQ-ACK codebook; herein, a first time is a boundary time for an active UL BWP change on the first serving cell, a start time for the first time unit being no earlier than the first time; the target serving cell is used to determine whether the first HARQ-ACK codebook comprises a HARQ-ACK information bit for the second time unit on the first serving cell.