Group-Based HARQ-ACK Feedback Mechanism for Wireless Data Retransmission
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Solution Overview
Problem
Existing HARQ mechanisms face challenges in efficiently acknowledging and retransmitting data over wireless channels due to poor signal quality and channel occupancy, leading to misaligned codebooks and unnecessary retransmissions.
Innovation Solution
A group-based HARQ-ACK feedback mechanism is introduced, where downlink transmissions are grouped into HARQ-ACK feedback groups with unique indices, allowing for dynamic formation and acknowledgment of groups, and incorporating a request mechanism to trigger retransmissions only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional HARQ mechanisms are used to acknowledge and retransmit data over wireless channels, then data retransmission can be performed, but unnecessary retransmissions occur and codebooks become misaligned due to poor signal quality and channel occupancy
Solution Approach 1:
The patent segments downlink transmissions into multiple HARQ-ACK feedback groups, each with a unique group index (GI). This segmentation allows the receiver to selectively acknowledge specific groups, improving feedback accuracy while reducing unnecessary retransmissions of already correctly received data groups.
Solution Approach 2:
The patent introduces dynamic formation of HARQ-ACK feedback groups where groups can be created, modified, or merged based on channel conditions and transmission requirements. The dynamic group indexing mechanism allows flexible acknowledgment patterns, enabling the system to adapt to varying signal quality and reduce wasteful retransmissions.
2Productivity
If multiple HARQ-ACK feedback groups are acknowledged over a single HARQ-ACK transmission opportunity, then feedback efficiency improves, but codebook alignment between transmitter and receiver becomes challenging
Solution Approach 1:
The patent implements a feedback mechanism where the receiver sends back the decoded group index (GI) values along with HARQ-ACK information. This feedback loop enables the transmitter to verify which groups were successfully received and acknowledged, ensuring codebook alignment even when multiple groups are acknowledged over a single transmission opportunity.
Solution Approach 2:
The group index (GI) acts as an intermediary element that bridges the transmitter and receiver. By embedding and echoing GI values in the HARQ-ACK feedback, the system maintains synchronization between transmitter and receiver codebooks, preventing misalignment issues when consolidating multiple feedback groups.
3Loss of energy
If group-based HARQ-ACK feedback is implemented with dynamic group formation, then unnecessary retransmissions are reduced, but the complexity of managing multiple feedback groups increases
Solution Approach 1:
The patent employs self-service mechanisms where the system automatically manages group formation and indexing based on predefined rules and channel conditions. The receiver autonomously determines which groups to acknowledge and generates appropriate feedback without requiring complex manual coordination, reducing the perceived complexity while maintaining efficiency.
Solution Approach 2:
The patent uses parameter changes in the form of group index (GI) values to manage feedback groups. By varying GI parameters to indicate different groups and their acknowledgment status, the system simplifies the management complexity compared to handling full group descriptors, enabling efficient control through compact parameter representation.
Data Source
AI summary
A method of a hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback mechanism includes receiving at a user equipment (UE) one or more first downlink control informations (DCIs) associated with first downlink transmissions belonging to a first HARQ-ACK feedback group. One of the first DCIs requests one or more second HARQ-ACK feedback groups to be acknowledged over a HARQ-ACK transmission opportunity (TxOP). A HARQ-ACK feedback for the first HARQ-ACK feedback group and the one or more second HARQ-ACK feedback groups is transmitted over the HARQ-ACK TxOP.