Precoding Vector Indication for Massive MIMO Feedback Overhead
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Solution Overview
Problem
Current precoding matrix feedback methods in Massive MIMO systems result in high feedback overheads, especially when the number of subbands increases, due to the need for independent reporting of subband combination coefficients, which hampers efficient spectrum resource utilization.
Innovation Solution
A method that involves generating and sending first indication information to indicate port selection vectors, frequency domain vectors, and linear combination coefficients, allowing the network device to determine a precoding matrix vector, thereby reducing feedback overheads by leveraging the relationship between subbands through a small quantity of frequency domain vectors and ensuring approximate precision of a Type II codebook.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal device performs wideband feedback and subband feedback based on each transport layer to improve precoding matrix precision, then the precoding matrix precision is improved, but the feedback overhead increases significantly
Solution Approach 1:
The patent combines wideband feedback and subband feedback into a unified feedback mechanism. Instead of performing separate feedback procedures for each transport layer, the system integrates the feedback processes to report precoding matrix information jointly, reducing redundant feedback while maintaining precision.
Solution Approach 2:
The feedback mechanism is designed to serve multiple transport layers simultaneously through a universal feedback structure. The same feedback information can be applied across different transport layers, eliminating the need for independent feedback per layer and significantly reducing overall feedback overhead.
2Productivity
If the network device transmits data through multiple transport layers to improve spectrum resource utilization, then spectrum resource utilization is improved, but the feedback overhead multiplies with the number of transport layers
Solution Approach 1:
The feedback mechanism is designed to serve multiple transport layers simultaneously through a universal feedback structure. The same feedback information can be applied across different transport layers, eliminating the need for independent feedback per layer and significantly reducing overall feedback overhead.
Solution Approach 2:
Instead of providing complete independent feedback for each transport layer, the system uses partial feedback that is sufficient for multiple layers. By reporting precoding matrix information that can be reused across transport layers, the system avoids excessive feedback while maintaining adequate precision for spectrum resource utilization.
Data Source
AI summary
This application provides methods and apparatuses for precoding vector indication and determination. One method includes: generating, by a first communications device, first indication information that indicates one or more port selection vectors, one or more frequency domain vectors, and one or more linear combination coefficients, wherein each of the one or more linear combination coefficients corresponds to a port selection vector and a frequency domain vector, each of the one or more port selection vectors indicates a port of a precoded reference signal, and each of the one or more frequency domain vectors indicates a variation pattern of a channel in a frequency domain; and sending the first indication information to a second communications device.