HARQ Acknowledgement Bit Allocation in 5G NR
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Solution Overview
Problem
In 5G NR communications systems, the high probability of downlink scheduling signaling loss leads to inconsistent bit allocation for HARQ acknowledgement information between network devices and terminals, resulting in failed decoding of acknowledgement information.
Innovation Solution
The network device sends downlink scheduling signaling that includes a threshold indicating the total quantity of downlink data, codewords, or code block groups, allowing the terminal to determine the correct number of bits for acknowledgement information, ensuring consistency and successful decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic configuration of HARQ acknowledgement information codebook is implemented in single CC scenario, then adaptability of the system is improved, but reliability of acknowledgement information decoding deteriorates due to high probability of downlink scheduling signaling loss
Solution Approach 1:
The network device performs preliminary action by indicating the threshold for the quantity of bits used for HARQ acknowledgement information in advance through downlink scheduling signaling. This allows the terminal to pre-determine the correct codebook size before feedback, ensuring both adaptability to dynamic scheduling and reliable decoding even if some signaling is lost, as the terminal can infer the correct configuration from the indicated threshold.
2Device complexity
If a single piece of downlink scheduling signaling is used to instruct HARQ acknowledgement feedback, then device complexity is reduced, but reliability of information transmission deteriorates due to high loss probability
Solution Approach 1:
The network device includes the threshold indication for HARQ acknowledgement bit quantity in the downlink scheduling signaling in advance. This preliminary inclusion ensures that even with a single piece of signaling, the terminal receives all necessary information to correctly determine the codebook size, maintaining reliability without increasing structural complexity.
3Adaptability or versatility
If the terminal determines HARQ acknowledgement bit quantity based on detected downlink scheduling information, then adaptability is improved, but measurement precision deteriorates when scheduling signaling is lost or skipped
Solution Approach 1:
The network device provides the threshold for HARQ acknowledgement bit quantity in advance through downlink scheduling signaling. This preliminary indication allows the terminal to accurately determine the correct codebook size based on the indicated threshold, rather than attempting to infer it from potentially lost or incomplete scheduling information, thus maintaining both adaptability and measurement precision.
Data Source
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AI summary
Embodiments of this application provide an acknowledgement information sending method and apparatus. When the acknowledgement information sending method provided in the embodiments of this application is applied, a network device determines and sends downlink scheduling signaling, where the downlink scheduling signaling is used to schedule first downlink data to a terminal, A is a positive integer, the first downlink data is downlink data corresponding to acknowledgement information fed back on a same uplink control channel, and the downlink scheduling signaling is used to determine a first threshold, a second threshold, or a third threshold. The terminal receives the downlink scheduling signaling sent by the network device, determines, based on the first threshold, the second threshold, or the third threshold, the acknowledgement information corresponding to the first downlink data, and sends the acknowledgement information corresponding to the first downlink data to the network device on the same uplink control channel. In the embodiments of this application, a quantity of bits of the acknowledgement information determined by the terminal can keep consistent with a quantity of bits of acknowledgement information determined by the network device.