HARQ Feedback Resource Selection for Unlicensed Communications
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Solution Overview
Problem
In wireless communication systems operating in unlicensed bands, there is a challenge in ensuring that base stations can reliably receive hybrid automatic repeat request (HARQ) responses from terminals due to the discontinuous use of resources, which can lead to undefined transmission resources for feedback information.
Innovation Solution
The method involves using downlink control information (DCI) to schedule physical downlink shared channels (PDSCH) with defined or undefined transmission resource information for HARQ responses, allowing terminals to transmit HARQ responses using resources indicated by subsequent DCI, and configuring HARQ codebooks based on PDSCH group indexes to manage resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If discontinuous resource use is implemented in unlicensed bands, then resource utilization efficiency is improved, but HARQ response transmission reliability deteriorates
Solution Approach 1:
The base station pre-configures multiple candidate HARQ response resources (PUCCH or PUSCH) for the terminal before actual data transmission. When the initially indicated resource becomes unavailable due to discontinuous resource use, the terminal can select from pre-configured alternative resources without requiring additional real-time signaling, thus maintaining reliable HARQ response transmission while allowing discontinuous resource allocation.
2Reliability
If additional signaling is used to ensure HARQ response transmission, then transmission reliability is improved, but system overhead increases
Solution Approach 1:
The base station configures multiple candidate HARQ response resources in advance through RRC signaling or MAC CE, so that when resource conflicts occur due to discontinuous resource use, the terminal can autonomously select appropriate resources from the pre-configured set without requiring additional real-time downlink control information, thereby ensuring reliability while minimizing overhead.
Solution Approach 2:
The terminal is empowered to autonomously determine which HARQ response resource to use based on pre-configured candidate resources and current channel conditions, without requiring continuous base station instructions. This self-service mechanism reduces signaling overhead while maintaining transmission reliability.
Data Source
AI summary
Disclosed are a method and an apparatus for transmitting or receiving feedback information in a communication system. An operation method of a terminal comprises the steps of: receiving, from a base station, DCI #1 including scheduling information of PDSCH #1 and transmission resource information of HARQ response #1 with respect to PDSCH #1; receiving, from the base station, DCI #2 including scheduling information of PDSCH #2 and transmission resource information of HARQ response #2 with respect to PDSCH #2; and when the transmission resource information of HARQ response #1 is configured as undefined, transmitting, to the base station, HARQ response #1 and HARQ response #2 by using a resource indicated by the transmission resource information of HARQ response #2. Therefore, the performance of the communication system can be improved.