Feedback Information Generation in Multi-User MIMO Systems
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Solution Overview
Problem
Closed-loop multi-user multi-antenna systems face inefficiencies in resource allocation due to high complexity and resource occupation in full feedback schemes, and suboptimal performance in single feedback schemes, especially when dealing with multiple users.
Innovation Solution
The method involves generating and transmitting feedback information based on similar vector sets formed from correlated column vectors in a precoding codebook, using a single feedback scheme that mimics the performance of multiple Channel Quality Information (CQIs, by selecting an index and data rate for each similar vector set and applying it to all similar vectors, allowing for efficient precoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full feedback scheme is used to transmit all data rates corresponding to all column vectors in codebook, then system performance is improved, but feedback information amount and system complexity increase significantly
Solution Approach 1:
The codebook column vectors are segmented into multiple groups based on correlation thresholds. Instead of treating all vectors individually, the patent divides them into correlated groups where vectors within each group have similar characteristics. This segmentation reduces the total number of feedback reports needed while maintaining performance for all vectors.
Solution Approach 2:
The patent uses a representative column vector from each correlated group to generate feedback information that is then applied to all vectors in that group. This copying approach allows a single feedback report to represent multiple codebook vectors, significantly reducing feedback overhead while maintaining accurate performance representation for all vectors in the group.
2Device complexity
If single feedback scheme is used to transmit only the index of column vector with highest data rate, then feedback information amount is reduced, but resource allocation optimization is compromised
Solution Approach 1:
The patent segments correlated column vectors into groups and generates separate feedback information for each group. This allows the system to optimize resource allocation for multiple vectors simultaneously rather than just a single vector, improving overall resource allocation efficiency while keeping feedback information manageable.
Solution Approach 2:
The patent performs preliminary correlation analysis and grouping of codebook vectors before feedback transmission. By pre-identifying correlated groups and selecting representative vectors in advance, the system prepares optimized feedback structures that enable efficient resource allocation without increasing real-time feedback overhead.
3Productivity
If multiple users are supported in closed-loop multi-antenna system, then system capacity increases, but feedback information management complexity and resource occupation increase
Solution Approach 1:
The patent merges feedback information for multiple users by grouping correlated column vectors across different users' codebooks. Users with similar channel characteristics can share feedback reports for their correlated vector groups, reducing redundant feedback transmission and simplifying feedback management while supporting multiple users.
Data Source
AI summary
A method and apparatus for transmitting/receiving feedback information in a multi-user multi-antenna system and a system supporting the same are provided, in which all possible combinations are created using column vectors included in a precoding codebook, column vectors are correlated in each of the combinations, column vectors comprising correlations exceeding a reference threshold are designated as similar vectors, at least two similar vector sets are formed with the similar vectors, and feedback information is generated based on the at least two similar vector sets and transmitted.