Uplink CQI Differential Feedback for URLLC Spectrum Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 5G communications, the current methods for URLLC service data transmission result in low spectrum resource utilization due to the use of hybrid automatic repeat request (HARQ) technology, which requires retransmitting data with a lower modulation and coding scheme, leading to inefficient use of frequency resources.
Innovation Solution
A data transmission method where a terminal device sends first and second channel quality indicators (CQIs) to a network device, allowing the network to adjust modulation and coding schemes based on the difference between the two CQIs, thereby optimizing spectrum resource utilization while maintaining reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station uses a lower MCS for retransmission to ensure reliability, then the URLLC service reliability is improved, but the spectrum resource utilization deteriorates
Solution Approach 1:
The patent applies dynamics by making the MCS selection adaptive rather than fixed. The network device dynamically adjusts the MCS for retransmission based on real-time CQI feedback from the terminal device. When channel conditions are good, a higher MCS is used for retransmission; when conditions are poor, a lower MCS is used. This dynamic adaptation resolves the contradiction by allowing the system to maintain reliability only when necessary while improving spectrum utilization when channel conditions permit higher efficiency transmission.
Solution Approach 2:
The patent changes the MCS parameter based on CQI feedback. Instead of always using a conservative lower MCS for retransmission, the system adjusts the MCS parameter according to the reported channel quality. The terminal device reports CQI values that reflect current channel conditions, and the network device uses this information to select an appropriate MCS, thereby changing the transmission parameter to optimize both reliability and spectrum efficiency under different conditions.
2Reliability
If the terminal device reports a smaller CQI to ensure higher transmission reliability, then the URLLC service reliability is improved, but the spectrum resource utilization deteriorates
Solution Approach 1:
The patent applies preliminary action by having the terminal device pre-calculate and report multiple CQI values corresponding to different target BLER levels (e.g., 10% and 0.1%) before actual data transmission. This allows the network device to have advance knowledge of the channel quality under different reliability requirements, enabling it to make informed MCS selection decisions that balance reliability and spectrum efficiency without being overly conservative.
Solution Approach 2:
The patent implements partial action by having the terminal device report only the necessary CQI information (differential values or selected CQIs) rather than complete channel state information. This partial reporting provides sufficient data for the network device to make MCS decisions that achieve the desired reliability level without the overhead of reporting all possible channel parameters, thus improving spectrum efficiency while maintaining reliability.
3Reliability
If the base station uses a lower MCS for both initial transmission and retransmission, then the URLLC service reliability is improved, but the spectrum resource utilization deteriorates
Solution Approach 1:
The patent applies segmentation by separating the MCS selection for initial transmission from the MCS selection for retransmission. Instead of using a single conservative MCS for both, the system independently determines appropriate MCS values based on the CQI feedback and target BLER requirements. This segmentation allows the initial transmission to use an optimized MCS for efficiency while retransmission uses an appropriately selected MCS based on actual channel conditions, resolving the contradiction between reliability and resource utilization.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
This application provides a data transmission method, a terminal device, and a network device. The method includes: sending, by a terminal device, first information to a network device, where the first information is used to indicate a first channel quality indicator CQI corresponding to a first block error rate; and sending, by the terminal device, second information to the network device by using radio resource control RRC signaling or media access control MAC signaling, where the second information is used to indicate a difference between the first CQI and a second CQI, the second CQI is a CQI corresponding to a second block error rate, and the first block error rate is greater than the second block error rate. According to the data transmission method, the terminal device, and the network device that are provided in this application, spectrum resource utilization can be improved while reliability of a URLLC service is ensured.