Decoupled Channel Quality and ACK/NACK Feedback Transmission
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Solution Overview
Problem
Current wireless communication systems face challenges in performing link adaptation quickly enough due to the limitations of Hybrid Automatic Repeat Request (HARQ) and Channel Quality Information (CQI) reporting/processing timelines, particularly in low latency systems, where faster adaptation is needed.
Innovation Solution
The technique involves decoupling the transmission of channel quality feedback, such as Signal-to-Noise-Plus-Interference Ratio (SNIR), from ACK/NACK feedback, allowing for earlier transmission of SNIR during one time interval (TTI) while reserving ACK/NACK feedback for a later TTI, enabling faster link adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If HARQ and CQI reporting/processing timelines are used for link adaptation, then feedback transmission is coordinated and simplified, but the speed of link adaptation is insufficient for low latency systems
Solution Approach 1:
The patent segments the coupled feedback transmission into two separate transmissions: channel quality feedback (e.g., SNIR) transmitted in a first uplink TTI, and ACK/NACK feedback transmitted in a second uplink TTI. This segmentation allows the channel quality feedback to be transmitted and processed earlier, thereby increasing link adaptation speed without compromising the coordination function of the coupled approach.
2Productivity
If channel quality feedback and ACK/NACK feedback are transmitted together, then feedback coordination is maintained, but link adaptation speed is limited by the later TTI timing
Solution Approach 1:
The patent applies preliminary action by transmitting channel quality feedback (SNIR) in advance in the first uplink TTI, before the ACK/NACK feedback is transmitted in the second uplink TTI. This preliminary transmission of channel quality information enables the base station to perform link adaptation earlier, improving productivity while the later ACK/NACK transmission maintains proper feedback coordination.
Data Source
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AI summary
Techniques are described for wireless communication at a user equipment (UE). One method includes receiving a downlink grant for a downlink transmission; transmitting channel quality feedback at a first time triggered by receipt of the downlink grant, the first time occurring during a first transmission time interval (TTI); and transmitting acknowledgement/negative-acknowledgement (ACK/NACK) feedback for the downlink transmission at a second time triggered by receipt of the downlink grant, the second time occurring during a second TTI, and the second TTI occurring later in time than the first TTI.