HARQ-ACK Control Signaling With Unified Codebook Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 5G communication systems, the variable HARQ-ACK delay and the use of code block groups (CBGs) as granularity for HARQ-ACK feedback pose challenges in designing downlink and uplink control signaling to determine HARQ-ACK codebooks and carry the feedback in a unified manner, especially when multiple downlink time units contribute to a single uplink time unit.
Innovation Solution
A method for determining HARQ-ACK codebooks based on data and control signaling, involving conversion of assignment index fields into a unified number of bits, and configuring HARQ-ACK timing units to ensure consistent encoding and decoding across different formats, using parameters like PDSCH-to-HARQ_feedback, slot offsets, and repetitive transmission schemes to align HARQ-ACK feedback between user equipment and base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable HARQ-ACK delay is implemented to support flexible scheduling in 5G, then scheduling flexibility and adaptability are improved, but the complexity of determining HARQ-ACK codebooks and aligning feedback timing between user equipment and base stations increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the relationship between downlink assignment index (DAI) values and HARQ-ACK codebook sizes. The base station pre-configures DAI fields in downlink control information (DCI) messages, and the user equipment uses these pre-defined DAI values to determine codebook sizes without complex real-time calculations. This resolves the contradiction by establishing predetermined rules that enable flexible scheduling while maintaining simple codebook determination procedures.
2Reliability
If code block groups (CBGs) are used as granularity for HARQ-ACK feedback instead of transport blocks, then feedback precision and reliability are improved, but the complexity of control signaling and codebook management increases
Solution Approach 1:
The patent applies segmentation by dividing transport blocks into code block groups (CBGs) as the feedback granularity. Each CBG is assigned a specific DAI value, allowing the user equipment to generate HARQ-ACK codebooks at the CBG level rather than the transport block level. This segmentation enables more precise and reliable feedback for individual code blocks while the DAI mechanism maintains signaling simplicity by providing a systematic way to track and acknowledge each CBG.
Solution Approach 2:
The patent changes the parameter of feedback granularity from transport blocks to code block groups. By modifying this fundamental parameter, the system achieves improved feedback reliability at the CBG level while the DAI field structure and codebook determination methods are adapted to work with the new granularity, preventing excessive complexity in control signaling.
3Productivity
If multiple downlink time units contribute to a single uplink time unit, then spectral efficiency and productivity are improved, but the difficulty of aligning HARQ-ACK feedback timing and ensuring consistent understanding between user equipment and base stations increases
Solution Approach 1:
The patent applies feedback by using DAI values as explicit indicators in downlink control information to guide user equipment in determining HARQ-ACK codebook sizes and timing. The DAI provides feedback-like information that tells the user equipment exactly how many CBGs need to be acknowledged and in what order, enabling accurate alignment of feedback timing even when multiple downlink time units contribute to a single uplink time unit. This resolves the timing alignment difficulty while maintaining high spectral efficiency.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present disclosure relates to a communication method and system for converging a 5th-generation (5G) communication system for supporting higher data rates beyond a 4th-generation (4G) system with a technology for internet of things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method performed by a second type of transceiver node in a wireless communication system is provided, comprising: receiving a first type of data and/or a first type of control signaling from a first type of transceiver node; determining an HARQ-ACK codebook and a time unit for transmitting the HARQ-ACK codebook based on the first type of data and/or the first type of control signaling; and transmitting the HARQ-ACK codebook to the first type of transceiver node in the determined time unit.