Grant-Free Uplink Buffering for Packet Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In grant-free uplink transmission mechanisms, data packet loss occurs when the network device fails to detect the initial data packet, leading to incorrect reception and subsequent loss of the first data packet, severely affecting data transmission reliability.
Innovation Solution
A method where the terminal device buffers the first data packet and sends a retransmitted data packet based on new data indication information, ensuring that the first data packet is not cleared from the buffer, even if the network device instructs the terminal device to send a second data packet using the same HARQ process number, thereby reducing packet loss and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the network device uses blind detection to obtain uplink control information, then the terminal device can directly perform uplink transmission without waiting for scheduling, but the network device may fail to detect the control information, leading to data packet loss
Solution Approach 1:
The terminal device performs preliminary actions by sending uplink control information (including HARQ process number) before the network device needs to schedule retransmission. This allows the network device to have advance knowledge of the HARQ process status, preventing blind detection failures from causing packet loss.
Solution Approach 2:
The terminal device provides feedback to the network device through uplink control information, reporting the HARQ process number and transmission status. This feedback mechanism enables the network device to make informed scheduling decisions rather than relying on blind detection, resolving the reliability issue while maintaining the speed benefits of grant-free transmission.
2Productivity
If the terminal device autonomously selects HARQ process for grant-free transmission, then transmission speed increases, but the network device cannot correctly receive data when blind detection fails
Solution Approach 1:
Uplink control information serves as an intermediary carrier that conveys HARQ process number and transmission status from the terminal device to the network device. This intermediary mechanism bridges the autonomy of grant-free transmission with the need for network device awareness, ensuring both high productivity and reliable reception.
3Ease of operation
If the network device schedules retransmission using UL grant information, then subsequent transmissions can be managed, but the terminal device may incorrectly assume initial transmission succeeded, causing data loss
Solution Approach 1:
The terminal device uses feedback from uplink control information (which the network device successfully received before blind detection failure) to determine whether to perform retransmission. When the network device sends UL grant for retransmission, the terminal device checks the previously sent feedback status to confirm whether the initial transmission was actually received, preventing incorrect assumptions and data loss.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of the present invention provide a data transmission method and apparatus. The method includes: sending, by a terminal device, a first data packet to a network device in a first time unit in a GUL transmission manner, where the first data packet corresponds to a first HARQ process number, and the first data packet corresponds to first new data indication information; receiving, by the terminal device, first instruction information sent by the network device, where the first instruction information is used to instruct the terminal device to send a second data packet in a second time unit, the second data packet corresponds to the first HARQ process number, and the second data packet corresponds to second new data indication information sent by the network device; and performing, by the terminal device, buffering processing on the first data packet or sending the second data packet, based on a value of the first new data indication information and a value of the second new data indication information. Therefore, a data packet loss can be reduced, and data transmission reliability is improved.