One-Shot HARQ Feedback NDI Configuration for Uplink Overhead Reduction
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Solution Overview
Problem
In wireless communication systems, particularly in unlicensed spectrum deployments, there is a challenge in efficiently managing hybrid automatic repeat request (HARQ) feedback due to uncertainties in channel access, leading to ambiguity in reporting new data indicators (NDI) and potential misinterpretation of ACK/NACK signals, which affects throughput and reliability.
Innovation Solution
The proposed solution involves configuring user equipment (UE) to selectively provide NDI with one-shot HARQ feedback based on specific indications, such as RRC information, MAC control elements, or grant associations, and using modified codebooks to handle ambiguity in SPS release feedback, thereby improving resource usage and reducing misinterpretation of HARQ feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NDI is always provided with one-shot HARQ feedback, then the base station can distinguish new data from retransmissions, but the uplink control channel overhead increases
Solution Approach 1:
The patent implements dynamic NDI reporting by configuring the UE to selectively include NDI in HARQ-ACK feedback based on higher-layer parameters (e.g., pusch-Config, pucch-Config) and downlink grant indications. This allows the system to adapt the NDI reporting behavior to current channel conditions and traffic patterns, providing NDI only when necessary to distinguish new data from retransmissions, thereby reducing unnecessary overhead while maintaining reliability.
Solution Approach 2:
The patent changes the parameter configuration of HARQ-ACK feedback by introducing configurable parameters that control NDI inclusion. Through RRC signaling and MAC CE, the system can modify whether NDI is reported in specific scenarios (e.g., when downlink assignment index is present, when specific DCI formats are received), allowing flexible adjustment of feedback content to balance reliability and overhead.
2Quantity of substance
If NDI is selectively provided based on indications, then uplink control channel overhead is reduced, but ambiguity in HARQ feedback interpretation may increase
Solution Approach 1:
The patent implements a layered feedback mechanism where higher-layer parameters (RRC, MAC CE) provide configuration feedback to the UE about when to include NDI, and physical layer downlink grants provide immediate indication feedback. This multi-layer feedback ensures that both UE and gNB have consistent understanding of NDI reporting conditions, eliminating ambiguity while allowing selective NDI transmission to reduce overhead.
Solution Approach 2:
The patent uses preliminary configuration through RRC signaling and MAC CE to establish NDI reporting rules before actual HARQ feedback transmission. By pre-configuring the conditions under which NDI should be reported (e.g., based on carrier activation state, bandwidth part configuration, or specific DCI formats), the system ensures that when NDI is selectively provided, both transmitter and receiver have prior agreement on the interpretation rules, preventing ambiguity.
3Adaptability or versatility
If one-shot HARQ feedback is used in unlicensed spectrum, then channel access uncertainty is handled, but confusion with SPS release feedback may occur
Solution Approach 1:
The patent segments the HARQ feedback mechanism by introducing distinct feedback types and associated parameters for different scenarios. One-shot HARQ feedback is separated from SPS release feedback through different codebook configurations and parameter sets. By segmenting the feedback mechanisms and providing separate configuration options, the system can handle channel access uncertainty in unlicensed spectrum while preventing confusion between different feedback types through clear differentiation in their respective parameter spaces.
Data Source
AI summary
This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer storage media, for one-shot hybrid automatic repeat request (HARQ) feedback for a user equipment (UE). In one aspect, a configuration of whether and in what circumstances a new data indicator (NDI) may be provided by the UE is disclosed. In another aspect, one or more rules for one-shot HARQ feedback reporting when the UE has received a semi-persistent scheduling (SPS) allocation release are disclosed.