NR Codebook Reporting for Time-Varying Downlink Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the New Radio (NR) system, the reporting of a precoding matrix indicator (PMI) does not adequately reflect the time-varying characteristics of the channel, leading to suboptimal downlink transmission performance.
Innovation Solution
A wireless communication method where a terminal device reports a target codebook using spatial, frequency, and time domain basis vectors, with the time domain basis vector reflecting channel information over N4 time units, enabling the network device to perform more accurate downlink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional precoding matrix indicator (PMI) is reported, then the reporting process is simple, but the downlink transmission performance is suboptimal because it does not reflect time-varying channel characteristics
Solution Approach 1:
The codebook is segmented into multiple codebook groups, each corresponding to different time units. The terminal device selects and reports only the target codebook from these groups that best matches the current channel conditions, rather than reporting a single static codebook. This segmentation allows the system to capture time-varying channel characteristics while managing reporting complexity through selective reporting.
Solution Approach 2:
The codebook reporting mechanism is made dynamic by introducing time-domain basis vectors and multiple codebook groups that adapt to changing channel conditions. The terminal device dynamically selects the most appropriate codebook from different time units based on current channel state, enabling the precoding matrix indicator to reflect real-time channel variations and improve downlink transmission performance.
2Reliability
If a codebook reflecting time-varying channel characteristics is reported, then downlink transmission performance improves, but the complexity of codebook structure and reporting increases
Solution Approach 1:
The codebook structure is extended into the time dimension by organizing codebooks into multiple groups, each associated with different time units and represented by time-domain basis vectors. This dimensional extension allows the system to capture temporal variations in channel characteristics. The terminal device selects codebooks from this time-dimensioned structure, enabling accurate representation of time-varying channels while maintaining a systematic and manageable codebook organization.
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
Wireless communication methods, terminal devices and network devices. A wireless communication method comprises: a terminal device reporting a target codebook to a network device, wherein the target codebook is represented by means of a spatial basis vector, a frequency-domain basis vector, a time-domain basis vector, and weighting coefficients corresponding to the spatial basis vector, the frequency-domain basis vector and the time-domain basis vector; and the time-domain basis vector is a vector with the length of N4, and the vector with the length of N4 corresponds to N4 first time units.