Precoding Vector Feedback Overhead Reduction via Space-Frequency Component Matrices
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Solution Overview
Problem
As the number of transport layers increases, the feedback overheads in existing methods for indicating precoding vectors in wireless communications multiply, leading to inefficiencies in spectrum utilization and data transmission.
Innovation Solution
A method is proposed where a terminal device generates and sends first indication information to indicate a limited set of L1 beam vectors, K1 frequency domain vectors, and T1 space-frequency component matrices, allowing the network device to determine a precoding vector for one or more frequency domain units, thereby reducing feedback overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two levels of feedback (wideband feedback and sub-band feedback) are used to indicate precoding vectors for each transport layer, then the network device can obtain precise precoding vectors, but feedback overheads multiply as the quantity of transport layers increases
Solution Approach 1:
The patent combines wideband feedback and sub-band feedback into a unified feedback mechanism. Instead of separately processing feedback for each transport layer, the system merges the feedback information and performs joint processing to determine precoding vectors, thereby reducing redundant feedback overhead while maintaining precision
Solution Approach 2:
The patent introduces a universal feedback mechanism that serves multiple transport layers simultaneously. By using a common set of beam vectors and frequency domain vectors that can be applied across different transport layers, the system reduces the need for separate feedback reports for each layer, thereby reducing overall feedback overhead
2Measurement precision
If a larger quantity of subbands is used to improve frequency domain resolution, then channel measurement accuracy improves, but feedback overheads increase significantly
Solution Approach 1:
The patent segments the frequency domain into a limited number of subbands and uses a common set of beam vectors and frequency domain vectors that can be applied across all subbands. This segmentation approach allows the system to maintain frequency domain resolution while avoiding the need to report separate precoding vectors for each subband, thereby reducing feedback overhead
Solution Approach 2:
The patent changes the feedback parameters from reporting full precoding vectors for each subband to reporting a reduced set of parameters (beam vector indices and frequency domain vector indices) that can be used to reconstruct precoding vectors. This parameter transformation reduces the amount of feedback data while maintaining the ability to achieve precise channel measurement
Data Source
AI summary
This disclosure provides methods and apparatuses for precoding in wireless communications. In an implementation, a method includes: receiving, from a terminal device, first indication information, wherein the first indication information indicates L1 space domain vectors in a space domain vector set, K1 frequency domain vectors in a frequency domain vector set, and T1 space-frequency component matrices, wherein a precoding vector of one or more frequency domain units is determined by a weighted sum of the T1 space-frequency component matrices, wherein the L1 space domain vectors and the K1 frequency domain vectors correspond to M1 space-frequency component matrices that comprise the T1 space-frequency component matrices, and determining the precoding vector of the one or more frequency domain units based on the first indication information.