5G HARQ-ACK Codebooks by Time Interval for Lower URLLC Latency
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Solution Overview
Problem
The 5G mobile communications technology faces challenges in ensuring reliability and low latency for ultra-reliable and low-latency communication (URLLC) services due to the current method of generating hybrid automatic repeat request-acknowledgment (HARQ-ACK) codebooks in units of slots, leading to increased latency and resource wastage.
Innovation Solution
Generating HARQ-ACK codebooks for each time domain interval less than one slot, allowing separate feedback of PUCCHs for different services without joint feedback, thereby reducing latency and resource wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If HARQ-ACK codebooks are generated in units of slot with joint feedback, then resource allocation is simplified, but latency increases and resource efficiency decreases
Solution Approach 1:
The patent segments the feedback mechanism by dividing HARQ-ACK codebook generation into separate time domain intervals within a slot. Instead of generating one joint codebook for the entire slot, the system generates multiple codebooks corresponding to different time domain intervals, allowing earlier intervals to be fed back independently without waiting for later intervals, thus reducing latency while maintaining manageable complexity through structured segmentation
2Loss of energy
If joint feedback is used for PUCCHs of different services, then resource management is simplified, but resource waste increases due to excessive allocation for reliability
Solution Approach 1:
The patent segments PUCCH feedback resources by service type and time domain interval. Different services (e.g., URLLC, eMBB) are assigned separate HARQ-ACK codebooks and PUCCH resources within the slot structure. This segmentation prevents high-reliability services from forcing excessive resource allocation on all PUCCHs, reducing resource waste while maintaining appropriate resource management through service-specific configurations
Solution Approach 2:
The patent applies local quality by allocating different resource levels to different services based on their specific requirements. High-reliability services like URLLC receive dedicated PUCCH resources with appropriate redundancy, while other services use standard allocations. This localized resource optimization avoids the blanket over-allocation that occurs with joint feedback, reducing overall resource waste while maintaining necessary reliability
3Loss of time
If joint encoding of ACK/NACK information is performed for all services in a slot, then encoding complexity is reduced, but feedback latency increases
Solution Approach 1:
The patent segments the encoding process by creating separate HARQ-ACK codebooks for different time domain intervals within a slot. Each codebook is encoded independently and fed back at its appropriate time, eliminating the need to wait for all services to complete before encoding begins. This segmentation reduces feedback latency while managing encoding complexity through modular, time-based separation of encoding tasks
Data Source
AI summary
This application provides an information transmission method and a communications device. The method includes: generating, by a terminal device, a hybrid automatic repeat request-acknowledgment HARQ-ACK codebook corresponding to an ith time domain interval, where the ith time domain interval is any one of N time domain intervals of one slot, i is less than or equal to N, i is a positive integer, and N is a positive integer greater than 1; determining, by the terminal device, a physical uplink control channel PUCCH resource corresponding to the HARQ-ACK codebook; and sending, by the terminal device, the HARQ-ACK codebook on the PUCCH resource.