Precoding Matrix Set Determination for Type II Codebook Restriction
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Solution Overview
Problem
In LTE and New Radio Access Technology systems, restricting precoding matrix subsets leads to a significant reduction in usable precoding matrices, resulting in deteriorated system performance due to the inability to effectively restrict vectors close to the restricted ones, and there is no technology to address this for Type II precoding matrices.
Innovation Solution
A method for determining a precoding matrix set by restricting product factors in W2 corresponding to vectors instead of directly prohibiting the vectors, allowing for a proper subset of precoding matrices to be used, thereby improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a specific vector is restricted in the precoding matrix subset, then the system can control interference and improve signal quality, but vectors close to the restricted vector are also excluded, resulting in a large quantity of precoding matrices being unavailable and system performance deteriorating
Solution Approach 1:
The patent applies local quality by differentiating between different types of restrictions: instead of uniformly restricting all vectors near a restricted vector, the invention selectively restricts only those vectors that would cause harmful interference while allowing vectors that do not. This is achieved by evaluating each candidate vector's specific impact on signal quality and interference characteristics, applying restriction only where locally necessary rather than globally.
Solution Approach 2:
The patent changes the parameter of vector restriction from a binary state (restricted or not restricted) to a graded state based on interference metrics. By introducing parameters such as interference threshold values and signal-to-interference ratio requirements, the system can dynamically adjust which vectors are restricted based on current channel conditions, thereby maintaining adaptability while controlling interference.
2Reliability
If prior-art restriction methods are applied to Type II precoding matrices, then vector interference can be controlled, but a relatively large quantity of precoding matrices cannot be used, leading to system performance deterioration
Solution Approach 1:
The patent segments the Type II precoding matrix structure into distinct components (W1 and W2 matrices with their respective vectors and coefficients) and applies restriction logic specifically to the appropriate segments. By focusing restriction on the interference-causing components rather than the entire matrix structure, the invention maintains more usable precoding matrices while still achieving interference control.
Solution Approach 2:
The patent introduces dynamic adjustment mechanisms that allow the set of restricted vectors to change based on channel conditions, rank indicators, and interference measurements. This dynamic approach ensures that the system adapts to varying conditions, maintaining high productivity by only restricting vectors when and where interference actually occurs, rather than applying static restrictions that reduce performance.
Data Source
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AI summary
This application provides a method for determining a precoding matrix set, so as to avoid a case in which a relatively large quantity of precoding matrices in a precoding matrix set cannot be used, thereby improving system performance. The method includes: receiving, by a terminal device, indication information; and determining, by the terminal device based on the indication information, a second precoding matrix set from a first precoding matrix set whose rank is R, where each precoding matrix W in the first precoding matrix set satisfies W = W1 × W2, the second precoding matrix set is a proper subset of the first precoding matrix set, and the second precoding matrix set does not include W = W1 × W2 that satisfies the specific condition in the first precoding matrix set.