Flexible HARQ Feedback Timing for Unlicensed Spectrum
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Solution Overview
Problem
In wireless communication systems, particularly in the NR system, the transmission of Hybrid Automatic Repeat Request (HARQ) information on the unlicensed spectrum faces challenges due to fixed PDSCH-HARQ feedback times, leading to scattered uplink resources and affecting network scheduling, especially when channel conditions are not ideal.
Innovation Solution
A method is introduced to flexibly feed back HARQ information on one or more time units satisfying the PDSCH-HARQ feedback timing, allowing for dynamic allocation of uplink and downlink resources on the unlicensed spectrum, ensuring communication link delay and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed PDSCH-HARQ feedback time is used, then the feedback timing is simple and deterministic, but the uplink resources become scattered and network scheduling is affected
Solution Approach 1:
The patent applies dynamics by making the PUCCH transmission timing flexible rather than fixed. The terminal device determines the actual transmission time unit based on channel detection results (CCA) and the predetermined time relationship, allowing the system to adapt to varying channel conditions while maintaining a structured timing framework through the parameter k.
Solution Approach 2:
The patent changes the timing parameter dynamically by introducing a time unit offset k that relates the downlink data reception time to the uplink feedback transmission time. This parameter allows the system to adjust feedback timing based on channel availability while maintaining a predictable relationship between downlink and uplink transmissions.
2Stability of the object's composition
If PUCCH resources are determined according to fixed feedback time, then the timing relationship is clear, but the resources are scattered on unlicensed spectrum
Solution Approach 1:
The patent makes the resource allocation dynamic by allowing the terminal to select different uplink time units based on channel detection outcomes. The timing relationship remains stable through the predetermined parameter k, while the actual resource selection adapts to channel conditions, resolving the contradiction between stability and flexibility.
Solution Approach 2:
The patent uses parameter k to maintain a stable timing relationship between downlink PDSCH and uplink PUCCH while allowing flexible resource selection. The parameter serves as a bridge that preserves timing structure while enabling adaptation to unlicensed spectrum channel conditions through CCA-based decisions.
3Reliability
If terminal performs channel detection before sending PUCCH, then channel conditions are considered, but transmission delay increases when channel is busy
Solution Approach 1:
The patent applies preliminary action by having the terminal perform channel detection (CCA) in advance of the intended PUCCH transmission time. This allows the terminal to identify suitable transmission opportunities beforehand and adjust its feedback timing proactively, reducing delays caused by channel unavailability while ensuring reliable transmission when conditions permit.
Data Source
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AI summary
Disclosed are a method and apparatus for transmitting HARQ information, and a computer storage medium. The method comprises: a terminal device determines first HARQ information, the first HARQ information being HARQ information corresponding to a first downlink data channel and received by the terminal device on a first downlink time unit, the first downlink data channel corresponding to a first time sequence value, and the first downlink time unit being a time unit in a first downlink transmission opportunity; and the terminal device transmits first uplink control information on a first uplink time unit, the first uplink control information comprising the first HARQ information, the first uplink time unit being a time unit in a first uplink transmission opportunity, the first uplink transmission opportunity being later than the first downlink transmission opportunity, and a time distance between the first uplink time unit and the first downlink time unit being greater than or equal to the first time sequence value.