GC-PDCCH HARQ Feedback Scheduling in Unlicensed Bands
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Solution Overview
Problem
In unlicensed bands, channel availability for hybrid automatic repeat request (HARQ) acknowledgement information transmission is uncertain due to contention-based access, leading to potential channel unavailability at specified times.
Innovation Solution
A method and system for HARQ feedback using group common physical downlink control channel (GC-PDCCH) to transmit downlink control information (DCI) for triggering HARQ acknowledgement information feedback, including RRC signaling for RNTI and PUCCH resource configuration, enabling simultaneous feedback for multiple terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If contention-based access is used in unlicensed bands, then channel sharing efficiency is improved, but channel availability uncertainty increases
Solution Approach 1:
The network device performs clear channel assessment (CCA) in advance before the terminal is scheduled to transmit HARQ feedback. This preliminary action determines whether the channel will be available at the expected time, allowing the system to prepare appropriate fallback mechanisms if the channel turns out to be unavailable due to contention-based access.
Solution Approach 2:
The patent introduces an intermediary mechanism where the network device monitors the channel status and dynamically adjusts the feedback transmission strategy. When CCA indicates the channel will be unavailable, the network device can schedule alternative feedback opportunities or use other communication paths, mediating between the terminal's feedback need and the channel's uncertain availability.
2Reliability
If traditional HARQ feedback mechanism is used, then feedback reliability is maintained, but channel monitoring overhead increases
Solution Approach 1:
The patent combines the channel monitoring function with the existing downlink control information transmission mechanism. The network device uses the same CCA process and channel assessment infrastructure already in place for downlink scheduling to also determine uplink feedback opportunities, merging two functions into a single process and avoiding duplicate monitoring overhead.
Solution Approach 2:
The clear channel assessment mechanism serves multiple purposes: it is used for downlink channel availability determination, uplink feedback scheduling, and conflict resolution in the shared unlicensed spectrum. This multi-functionality eliminates the need for separate dedicated monitoring mechanisms, reducing overall system overhead while maintaining feedback reliability.
3Loss of time
If dedicated feedback channel is allocated, then feedback timing is precise, but system flexibility decreases
Solution Approach 1:
The patent implements dynamic feedback scheduling where the terminal and network device can adaptively select feedback transmission opportunities based on real-time channel conditions and contention status. Rather than relying on a fixed dedicated channel, the system dynamically determines when feedback can be reliably transmitted, maintaining timing precision while preserving flexibility to handle various channel scenarios.
Data Source
AI summary
A method for HARQ feedback, a terminal, and a network device are provided. The method includes: obtaining DCI in a GC-PDCCH; and feeding back HARQ acknowledgement information according to the DCI.