Precoding Vector Feedback via Frequency Domain Grouping
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Solution Overview
Problem
Current precoding vector feedback methods in Massive MIMO systems do not achieve high precision while maintaining equivalent overheads, as they often fail to accurately reflect channel changes due to discontinuous or sparse frequency domain unit distributions, leading to poor continuity and increased overheads.
Innovation Solution
The method involves grouping frequency domain units into groups and performing dual-domain compression, allowing for the selection of frequency domain vectors of different lengths for each group, enabling better reflection of channel changes and improved feedback precision by determining proper frequency domain vectors based on the quantity and distribution of units within each group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If dual-domain compression is performed based on the entire reporting bandwidth using a single set of frequency domain vectors, then feedback overheads are reduced, but the frequency domain vector cannot accurately reflect channel changes due to discontinuous or sparse frequency domain unit distribution
Solution Approach 1:
The reporting bandwidth is divided into multiple frequency domain unit groups, where each group contains one or more frequency domain units. This segmentation allows the terminal device to perform dual-domain compression separately for each group, enabling the selection of frequency domain vectors with different lengths adapted to the distribution characteristics of frequency domain units in each group, thereby improving feedback precision while controlling overheads
Solution Approach 2:
Different frequency domain unit groups can use frequency domain vectors of different lengths based on their local characteristics. Groups with dense frequency domain unit distribution can use shorter vectors, while groups with sparse or discontinuous distribution can use longer vectors, achieving local optimization of feedback precision without uniformly increasing overheads across the entire bandwidth
2Reliability
If frequency domain vectors with length equal to the quantity of frequency domain units for which reporting is to be performed are used, then overheads are reduced, but the obtained frequency domain vector cannot accurately reflect channel change law due to poor continuity of frequency domain unit distribution
Solution Approach 1:
The length of frequency domain vectors is made dynamic and adaptable to different frequency domain unit groups rather than being fixed. The terminal device can determine appropriate vector lengths based on the quantity and distribution characteristics of frequency domain units in each group, allowing the system to flexibly balance between accuracy and overheads for different channel conditions
Solution Approach 2:
The patent changes the parameter of frequency domain vector length from a fixed value to a variable that can be adjusted according to the specific characteristics of each frequency domain unit group. This parameter change enables the system to optimize feedback precision for groups with poor continuity by using longer vectors while maintaining low overheads for groups with good continuity using shorter vectors
Data Source
AI summary
The present disclosure relates to precoding vector indicating and determining methods and communications apparatus. In one example method, a terminal device generates first indication information, and sends the first indication information to a network device. The first indication information is used to indicate one or more frequency domain vectors and one or more weighting coefficients, where the one or more frequency domain vectors include a frequency domain vector reported for each of R frequency domain unit groups, the one or more weighting coefficients include a weighting coefficient reported for each of the R frequency domain unit groups, and a frequency domain vector and a weighting coefficient that are reported for an rth frequency domain unit group in the R frequency domain unit groups are used to construct a precoding vector corresponding to one or more frequency domain units in the rth frequency domain unit group.