HARQ Feedback Timing Control in 5G Wireless Systems
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Solution Overview
Problem
Current 5G mobile communication systems face challenges in providing flexibility in physical downlink shared channel (PDSCH) and physical uplink shared channel (PUSCH) scheduling, particularly in determining Hybrid Automatic Repeat and Request (HARQ) feedback timing, which affects transmission efficiency and reliability.
Innovation Solution
A method and apparatus that involve a user equipment (UE) and a base station (BS) exchanging downlink control information (DCI) with a hybrid automatic repeat and request (HARQ) feedback timing indicator, where the UE determines the HARQ feedback slot based on the indicator, and transmits HARQ feedback only when the indicator value is numerical, ensuring synchronized and efficient HARQ feedback transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If HARQ feedback timing is determined using a non-numerical indicator value, then scheduling flexibility is improved, but feedback transmission timing becomes uncertain and may delay error correction
Solution Approach 1:
The system dynamically adjusts HARQ feedback transmission behavior based on the DCI format type. When DCI format 1_0 is used with a non-numerical HARQ feedback timing indicator, the UE suppresses feedback transmission to maintain scheduling flexibility. When DCI format 1_1 or 1_2 is used or a numerical value is provided, the UE transmits feedback at the indicated time to ensure timely error correction. This dynamic adaptation resolves the contradiction between flexibility and timing certainty.
Solution Approach 2:
The patent changes the interpretation of the HARQ feedback timing indicator parameter based on the DCI format. For DCI format 1_0, a non-numerical value (e.g., -1) indicates feedback suppression, while for DCI formats 11 and 12, the same field indicates a specific timing value. This parameter interpretation change allows the system to achieve both scheduling flexibility and timely feedback transmission as needed.
2Reliability
If HARQ feedback timing indicator is always provided as a numerical value, then feedback transmission timing is certain, but scheduling flexibility is reduced
Solution Approach 1:
The system dynamically selects between providing a specific HARQ feedback timing (numerical value) and allowing flexible scheduling (non-numerical value) based on the DCI format type and current scheduling requirements. This dynamic selection enables the system to prioritize reliability when needed and flexibility when needed, resolving the contradiction between these two objectives.
Solution Approach 2:
The HARQ feedback timing indicator field in DCI serves multiple functions: it can indicate a specific timing value for reliable feedback transmission, or it can indicate feedback suppression for flexible scheduling. This multi-functionality allows a single field to address both reliability and flexibility requirements, resolving the contradiction between them.
3Device complexity
If DCI format 10 is used for PDSCH scheduling, then device complexity is reduced, but HARQ feedback control flexibility is limited
Solution Approach 1:
DCI format 110 is designed to universally handle both simple and flexible HARQ feedback scenarios. The format includes a HARQ feedback timing indicator field that can be interpreted in multiple ways (numerical value for specific timing, non-numerical value for feedback suppression), enabling the simple format to provide flexible HARQ control when needed without increasing device complexity.
Solution Approach 2:
The interpretation of the HARQ feedback timing indicator parameter in DCI format 110 changes based on the indicator value. When the value is non-numerical (e.g., -1), it indicates feedback suppression, providing flexibility. When a numerical value is provided, it indicates specific timing. This parameter interpretation mechanism enables flexible HARQ control within the simple DCI format 110 structure.
Data Source
AI summary
The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Provided is a method performed by a user equipment (UE), the method including receiving downlink control information (DCI) scheduling a plurality of physical downlink shared channels (PDSCHs); identifying a value of a hybrid automatic repeat and request (HARQ) feedback timing indicator included in the received DCI; and performing the HARQ feedback transmission, based on the identified value of the HARQ feedback timing indicator, wherein in case that the value is identified as a non-numerical value, HARQ feedback information for the plurality of PDSCHs is not transmitted based on the DCI and the HARQ feedback information for the plurality of PDSCHs is transmitted after an other DCI including a numerical value of the HARQ feedback timing indicator is received.