HARQ-ACK Codebook Generation for Delayed Feedback in 5G NR
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Solution Overview
Problem
In 5G New Radio (NR) systems, existing techniques face challenges in ensuring effective feedback of Semi-Persistent Scheduling (SPS) PDSCH HARQ-ACK, particularly in determining and transmitting HARQ-ACK information across multiple serving cells with delayed feedback slots, which affects communication quality and terminal device performance.
Innovation Solution
A retransmission response feedback method that traverses serving cells to determine HARQ-ACK information for both original and delayed downlink slots, generates a HARQ-ACK codebook based on this information, and transmits it using an uplink channel, ensuring effective feedback of SPS PDSCH HARQ-ACK by arranging the codebook in ascending order of SPS configuration and serving cell indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE transmits HARQ-ACK information in the slot indicated by K1 offset, then the feedback timing is determined, but when the indicated slot is a downlink slot, the feedback cannot be transmitted timely
Solution Approach 1:
The patent applies dynamics by making the feedback slot selection flexible rather than fixed. The UE dynamically determines whether to use the originally indicated feedback slot or a delayed feedback slot based on real-time conditions (whether the indicated slot is available for uplink transmission). This dynamic adjustment resolves the contradiction between maintaining scheduled feedback timing and ensuring actual feedback effectiveness.
Solution Approach 2:
The patent changes the feedback slot parameter from a fixed K1-indicated value to a variable value that can be either the original slot or a delayed slot. By allowing the feedback slot parameter to change based on availability conditions, the system maintains reliable feedback while adapting to timing constraints.
2Device complexity
If the UE has only one PUCCH carrying HARQ-ACK information in one slot, then the resource configuration is simplified, but multiple serving cells with different feedback slots cannot be handled effectively
Solution Approach 1:
The patent segments the HARQ-ACK feedback process into multiple independent parts: identifying original downlink slots, identifying delayed downlink slots, and processing feedback for each cell separately. This segmentation allows the UE to handle multiple serving cells with different feedback timing requirements independently, maintaining simplicity while achieving multi-cell adaptability.
Solution Approach 2:
The patent adds a time dimension to the feedback mechanism by introducing delayed feedback slots. Instead of being constrained to a single feedback slot per cell, the system operates across multiple time dimensions, allowing flexible accommodation of multiple serving cells with different K1 offsets without increasing structural complexity.
3Reliability
If SPS PDSCH HARQ-ACK feedback is delayed to a later slot, then the feedback can be transmitted in an available uplink slot, but the feedback timing flexibility is reduced
Solution Approach 1:
The patent applies dynamics by making the feedback slot selection flexible rather than fixed. The UE dynamically determines whether to use the originally indicated feedback slot or a delayed feedback slot based on real-time conditions (whether the indicated slot is available for uplink transmission). This dynamic adjustment resolves the contradiction between maintaining scheduled feedback timing and ensuring actual feedback effectiveness.
Data Source
AI summary
A retransmission response feedback method and apparatus are provided. The method includes: traversing serving cells to determine HARQ-ACK of an original downlink slot and a delayed downlink slot in each serving cell for which an uplink channel resource requires feedback, wherein the original downlink slot refers to a downlink slot corresponding to an ACK/NACK feedback determined based on a slot offset K1 from a PDSCH to the ACK/NACK feedback, and the delayed downlink slot refers to a downlink slot in which the ACK/NACK feedback determined based on the slot offset K1 is transmitted with a delay; acquiring HARQ-ACK information of the original downlink slot and HARQ-ACK information of the delayed downlink slot, respectively; generating a HARQ-ACK codebook based on the HARQ-ACK information of the original downlink slot and the HARQ-ACK information of the delayed downlink slot; and transmitting the HARQ-ACK codebook using an uplink channel.