HARQ Feedback COT Association for Channel Access
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Solution Overview
Problem
In scenarios where both base stations and terminals have frame-based equipment configurations, overlapping channel occupancy times can lead to ambiguity in determining whether hybrid automatic repeat request (HARQ) feedback transmission is associated with the base station's or terminal's configuration, resulting in difficulties in channel access and data transmission.
Innovation Solution
A method is provided to determine whether a target time domain position for sending HARQ feedback information is within a specific channel occupancy time (COT), allowing the terminal to directly use the COT associated with the base station or itself for transmission without the need for clear channel assessment (CCA), depending on overlap conditions and signaling indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal performs clear channel assessment (CCA) before sending HARQ feedback information, then channel access reliability is improved, but channel access time delay increases and access efficiency deteriorates
Solution Approach 1:
The base station performs CCA and acquires channel occupancy time (COT) before the terminal needs to send HARQ feedback. The base station pre-configures the terminal with COT configuration information including time domain positions where CCA can be skipped. This preliminary action by the base station eliminates the need for the terminal to perform CCA at these pre-configured positions, reducing time delay while maintaining reliability through advance planning
Solution Approach 2:
The base station acts as an intermediary that performs CCA on behalf of the terminal and provides COT configuration information to the terminal. This intermediary approach allows the terminal to skip CCA at specific time domain positions while the base station maintains channel access reliability through its own CCA performance and COT management
2Productivity
If the terminal skips CCA at pre-configured time domain positions, then channel access efficiency is improved, but ambiguity in COT association increases
Solution Approach 1:
The COT configuration information is segmented into multiple time domain positions within the COT. Each time domain position is clearly defined with specific start and end times. The terminal is provided with segmented CCA skipping opportunities at these specific positions, which reduces ambiguity by clearly delineating when CCA can be skipped versus when it should be performed
Solution Approach 2:
The COT configuration information is dynamically adjusted based on channel conditions and traffic requirements. The base station can update the time domain positions where CCA can be skipped, allowing the system to adapt to changing conditions while maintaining clear COT association. This dynamic configuration ensures that the terminal always has up-to-date information about valid CCA skipping positions
Data Source
AI summary
An HARQ feedback method, performed by a terminal, includes: obtaining a first determination result by determining whether a target time domain position for sending HARQ feedback information is located within a first channel occupancy time (COT) where a target physical downlink shared channel (PDSCH) transmitted by a base station is located, where the HARQ feedback information is HARQ feedback information corresponding to the target PDSCH; and based on the first determination result, determining a target COT associated with the target time domain position.