Dynamic Feedback Compression for Fewer ACK-to-NACK Errors
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Solution Overview
Problem
In wireless communications systems, especially for cell-edge UEs with poor coverage, lossy compression of feedback payloads increases ACK-to-NACK errors, leading to unnecessary retransmissions and reduced downlink throughput.
Innovation Solution
A control message dynamically indicates compression parameters for lossy compression of feedback payloads, allowing UEs to adapt to channel conditions, reducing the payload size while minimizing ACK-to-NACK errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lossy compression is applied to feedback payloads, then payload size is reduced and processing overhead is decreased, but ACK-to-NACK errors increase leading to unnecessary retransmissions
Solution Approach 1:
The patent implements dynamic compression parameter indication where the network entity selects and signals different compression parameters based on current channel conditions. This allows the compression level to adapt dynamically - using stronger compression when channel conditions are good and reducing compression when conditions deteriorate, thus resolving the contradiction between payload size reduction and feedback accuracy maintenance.
Solution Approach 2:
The patent changes the compression parameters dynamically based on channel quality indicators. The network entity monitors channel conditions and adjusts compression parameters (such as compression ratio, bundling level, or feedback bit mapping) accordingly. This parameter adaptation allows the system to optimize the balance between feedback payload size and accuracy for each transmission scenario.
2Reliability
If compression parameters are dynamically adjusted, then feedback reliability is improved by adapting to channel conditions, but control signaling overhead increases
Solution Approach 1:
The patent applies local quality by indicating compression parameters only when and where they are needed - specifically in the downlink control information (DCI) messages that schedule downlink transmissions. The compression parameters are locally adapted to each downlink grant or indication, allowing precise control without blanket overhead across all signaling. This localized approach minimizes overall signaling overhead while maintaining reliability where critical.
Solution Approach 2:
The patent integrates compression parameter indication into existing DCI structures that already serve multiple purposes (scheduling, resource allocation, modulation and coding scheme indication). By embedding compression parameters within these multi-functional control messages, the patent avoids creating separate dedicated signaling channels, thus minimizing additional overhead while achieving dynamic adaptation.
3Productivity
If aggressive compression is used to minimize retransmissions, then resource efficiency improves, but processing complexity at the UE increases
Solution Approach 1:
The patent applies preliminary action by providing the compression parameters to the UE in advance through downlink control information before the UE needs to generate and transmit feedback. The UE receives the compression parameter indication, stores it, and then applies the appropriate compression algorithm when generating feedback. This pre-provisioning of parameters simplifies UE processing compared to real-time adaptive compression, reducing device complexity while maintaining resource efficiency.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a control message that indicates one or more parameters for lossy compression of a feedback payload. The one or more parameters may indicate at least a compression ratio between an original feedback payload size and a compressed feedback payload size. The one or more parameters may also indicate a bundle size, a quantity of bundles, a quantity of most likely outcomes to distinguish, a quantity of negative acknowledgments (NACKs) to be distinguished, or a combination thereof. The UE may monitor for one or more downlink transmissions associated with the feedback payload and transmit the feedback payload based on the one or more downlink transmissions. The feedback payload may be compressed from the original feedback payload size to the compressed feedback payload size in accordance with the one or more parameters.