DCI Field Reinterpretation for HARQ-ACK Feedback in Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transmitting explicit HARQ-ACK feedback, leading to unnecessary repeated transmissions and increased power consumption, particularly in scenarios with sporadic packet arrivals like URLLC services, where existing methods require significant DCI resources for HARQ-ACK feedback.
Innovation Solution
The method involves interpreting and utilizing specific DCI fields to explicitly convey HARQ-ACK information, such as using the NDI field with fixed values or RV and HARQ ID fields, to reduce unnecessary resource allocation and power consumption by distinguishing between HARQ-ACK and PUSCH resource allocation, thereby minimizing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing DCI resources are used for HARQ-ACK feedback transmission, then HARQ-ACK feedback can be transmitted, but it causes unnecessary repeated transmissions and increased power consumption
Solution Approach 1:
The patent applies multi-functionality by enabling DCI fields to serve dual purposes: their traditional functions and HARQ-ACK feedback transmission. Specifically, the NDI field is reinterpreted to carry HARQ-ACK information when UL grant is absent, while the RV field and HARQ ID field are used to convey additional HARQ-ACK details. This allows a single DCI message to simultaneously provide scheduling information and explicit HARQ-ACK feedback, eliminating the need for separate feedback transmissions and reducing power consumption.
2Loss of information
If DCI fields are reused for HARQ-ACK indication, then signaling overhead is reduced, but it requires reinterpreting field values and adding complexity to DCI interpretation
Solution Approach 1:
The patent implements dynamics by making the interpretation of DCI fields context-dependent. The NDI field is interpreted differently based on the presence or absence of UL grant in the DCI message: when UL grant is present, NDI indicates new data transmission; when UL grant is absent, NDI conveys HARQ-ACK feedback. This dynamic interpretation rule allows the system to reduce signaling overhead without requiring separate dedicated fields, as the same field adapts its meaning based on the message context.
Solution Approach 2:
The patent applies parameter changes by altering the semantic meaning of existing DCI field values rather than introducing new fields. The NDI field, traditionally using binary values to indicate new versus retransmission, is reparameterized to encode HARQ-ACK information (ACK, NACK, DTX) when UL grant is absent. Similarly, the RV field and HARQ ID field are reparameterized to carry additional HARQ-ACK related information, thereby reducing signaling overhead while utilizing existing field structures.
3Loss of information
If NDI field is used to indicate HARQ-ACK feedback, then additional HARQ-ACK information can be conveyed, but it creates ambiguity in distinguishing between NDI for new data indication and NDI for HARQ-ACK indication
Solution Approach 1:
The patent resolves the ambiguity through a dynamic interpretation mechanism based on the presence of UL grant. When UL grant is present in the DCI message, the NDI field is interpreted as indicating new data transmission versus retransmission. When UL grant is absent, the same NDI field is interpreted as carrying HARQ-ACK feedback information. This context-dependent interpretation rule, clearly defined in the patent, eliminates ambiguity by providing deterministic rules for field interpretation based on message structure.
Data Source
AI summary
The present disclosure provides a method for receiving a HARQ-ACK feedback and an apparatus supporting the same. More particularly, the method performed by a user equipment includes transmitting, to a base station, an uplink data; and receiving, from the base station, first DCI for the uplink data, wherein the first DCI includes a New Data Indicator (NDI) field indicating a transmission or retransmission of the uplink data, wherein the first DCI is determined by DCI related to HARQ-ACK of the uplink data on whether the first DCI includes a UL grant, and when the first DCI is determined to be the DCI related to HARQ-ACK of the uplink data, wherein the NDI field is identified to be related to the HARQ-ACK of the uplink data.