HARQ-ACK Codebook Retransmission via DCI Field Reuse
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Solution Overview
Problem
Existing wireless communication technologies face challenges in efficiently indicating the retransmission of canceled or dropped Hybrid Automatic Repeat Request (HARQ) codebooks without increasing signaling overhead or blind detection complexity for user devices, particularly in scenarios involving overlapping high- and low-priority HARQ-ACK codebooks.
Innovation Solution
The proposed techniques utilize physical-layer control signaling messages, such as DCI, to indicate attributes of the HARQ-ACK codebooks, including size, priority, and offset values, by reinterpreting existing DCI fields like DAI to facilitate retransmission without additional overhead, and configure HARQ process sets through RRC signaling to manage codebook reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods are used to retransmit canceled HARQ-ACK codebooks, then feedback reliability is improved, but signaling overhead increases
Solution Approach 1:
The patent reuses existing DCI formats and fields (such as Downlink Assignment Index, resource assignment fields) for dual purposes: their original functions plus indicating codebook retransmission attributes. This allows the system to trigger codebook retransmission without allocating dedicated signaling resources, thereby improving feedback reliability while avoiding additional signaling overhead.
Solution Approach 2:
The system uses already-configured RRC parameters and existing DCI structures to self-configure the codebook retransmission mechanism. By leveraging pre-configured HARQ process sets and reinterpreting existing field combinations, the system eliminates the need for separate configuration signaling, reducing overhead while maintaining reliable retransmission capability.
2Reliability
If existing methods are used to retransmit canceled HARQ-ACK codebooks, then feedback reliability is improved, but blind detection complexity increases
Solution Approach 1:
The patent employs existing DCI formats that user equipment already monitors for downlink assignments. By embedding codebook retransmission triggers within these familiar formats using predetermined field interpretations, the system enables reliable codebook retransmission without requiring UE to detect new DCI types or formats, thus avoiding increased blind detection complexity.
Solution Approach 2:
The system pre-configures HARQ process sets and establishes field interpretation rules through RRC signaling before codebook retransmission is needed. This preliminary configuration allows UE to efficiently identify and process retransmission triggers using pre-established rules, reducing real-time detection complexity while ensuring reliable feedback recovery.
3Measurement precision
If codebook attributes are indicated with detailed signaling, then transmission accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent indicates codebook attributes by changing the interpretation of existing DCI field values rather than adding new fields. Specific bit patterns in resource assignment fields or DAI fields are redefined to encode codebook size, priority, or other attributes, achieving precise indication while utilizing already-allocated signaling bits, thus avoiding additional overhead.
Solution Approach 2:
Existing DCI fields serve multiple functions: their primary scheduling functions plus encoding codebook attributes. This multi-functionality allows accurate transmission of codebook information using the same signaling resources, eliminating the need for separate attribute indication channels and preventing overhead increase.
Data Source
AI summary
Methods, apparatus, and systems that facilitate the indication of the codebook to be transmitted/retransmitted are disclosed. In one example aspect, a method for wireless communication includes transmitting, by a base station, a physical-layer control signaling message to a user device triggering a retransmission of a codebook for a feedback transmission that has been previously canceled. The physical-layer control signaling message includes a field of resource assignment that is used to indicate an attribute associated with the codebook. The method also includes receiving, by the base station, the retransmission of the codebook from the user device according to the physical-layer control signaling message.