Downlink Feedback Timing With Symbol-Level Offset for Low Latency
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Solution Overview
Problem
Existing communication systems experience high transmission latency in downlink data due to the timing relationship between data receipt and feedback, particularly in ultra-reliable and low-latency communication services like unmanned driving and telemedicine, where reliability and latency requirements are stringent.
Innovation Solution
The method involves determining a second time unit for sending feedback information based on a non-negative integer k1, where the length of the first time unit is greater than or equal to the second time unit, and the length of the second time unit is less than one slot, allowing for optimized feedback timing and reduced latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the feedback timing follows the n+k1 slot relationship with k1=5, then the system maintains standardized timing alignment, but the downlink data transmission latency becomes relatively high
Solution Approach 1:
The patent segments the feedback timing into two distinct parts: a base offset K1 (in slots) and an additional offset K2 (in symbols within the slot). This segmentation allows the feedback timing to be precisely controlled at the symbol level rather than being constrained to slot boundaries, thereby reducing latency while maintaining standardized timing alignment through the K1 component.
Solution Approach 2:
The patent introduces a new dimension for timing control by adding symbol-level offset K2 within the slot structure. Instead of only adjusting feedback timing at the slot level (single dimension), the solution operates in two dimensions: slot offset K1 and symbol offset K2 within the slot. This enables finer-grained timing adjustment to reduce latency without disrupting the overall slot-based timing alignment.
2Productivity
If the feedback is sent at the end of each slot, then the timing alignment with resource allocation is simplified, but the data retransmission timeliness is reduced
Solution Approach 1:
The patent enables preliminary action by allowing feedback to be transmitted before the slot ends, specifically at an earlier symbol position determined by the K2 offset. This提前 feedback transmission gives the network device more time to process the feedback and initiate retransmission, improving data retransmission timeliness while the K1 offset maintains alignment with the resource allocation structure.
Solution Approach 2:
The patent changes the timing parameters from fixed slot-end transmission to flexible symbol-level transmission by introducing offset K2. The feedback timing is now determined by the parameter combination of K1 (slot offset) and K2 (symbol offset within slot), allowing dynamic adjustment of feedback timing to optimize retransmission speed while maintaining resource allocation alignment through standardized K1 values.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2~3A
AI summary
This application provides a communication method, including: A terminal device determines a first time unit for receiving downlink data, determines, based on k1 corresponding to the downlink data, a second time unit in which feedback information corresponding to the downlink data is located, where a length of the first time unit is greater than or equal to a length of the second time unit, k1 is a nonnegative integer, k1 represents a quantity of second time units from the first time unit to the second time unit, and the length of the second time unit is less than one slot slot, and sends, in the second time unit, a feedback codebook to the network device, where the feedback codebook includes the feedback information corresponding to the downlink data. In this application, a transmission latency of downlink data is reduced.