MU-MIMO Codebook Pruning for Sector Coverage and Low Feedback
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Solution Overview
Problem
Current Multiple-User Multiple-Input Multiple-Output (MU-MIMO) systems face challenges in optimizing codebooks for efficient data transmission, particularly in scenarios with multiple sectors, where existing codebooks may increase unnecessary complexity and reduce coverage.
Innovation Solution
A method for designing a MU-MIMO codebook by analyzing beam patterns of candidate vectors, eliminating unnecessary vectors based on coverage requirements, and optimizing the codebook to minimize size and interference, using specific vector sets such as [u1, u2, u4, u5, u6, u7, u8] or [u2, u13, u9, u5, u1, u16, u12, u8, u4] for base stations and terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a comprehensive codebook with all candidate vectors is used in MU-MIMO system, then the coverage of each sector is improved, but the codebook size and feedback bits increase unnecessarily
Solution Approach 1:
The patent extracts and eliminates unnecessary candidate vectors from the codebook by analyzing beam patterns. Specifically, vectors that produce redundant or overlapping beam patterns within sectors are identified and removed, keeping only the essential vectors needed for adequate sector coverage. This extraction process reduces codebook size while preserving the necessary coverage capability.
Solution Approach 2:
The patent changes the selection criteria for codebook vectors by introducing beam pattern analysis as a new parameter. Instead of using all candidate vectors uniformly, the system evaluates vectors based on their beam pattern characteristics and selectively retains those that provide unique and valuable coverage, eliminating vectors with redundant beam patterns.
2Productivity
If more candidate vectors are included in the codebook, then the data transmission efficiency is improved, but the interference between vectors increases
Solution Approach 1:
The patent converts the potentially harmful effect of vector interference into a beneficial selection criterion. By analyzing beam patterns, the system identifies vectors whose beam patterns naturally complement each other and minimize interference. The interference analysis is used to selectively retain vectors that, when combined, actually reduce overall system interference while maintaining high data transmission efficiency.
3Reliability
If a larger codebook is used to ensure complete coverage, then the reliability is improved, but the feedback bits and system complexity increase
Solution Approach 1:
The patent extracts only the essential vectors needed for complete sector coverage by analyzing beam patterns. Vectors that contribute redundant coverage information are eliminated, resulting in a minimized codebook that maintains complete coverage while reducing the number of feedback bits required to identify selected vectors.
Data Source
AI summary
Disclosed are a Multiple User Multiple Input Multiple Output (MU-MIMO) codebook design method, and a communication device using the codebook. A MU-MIMO codebook design method includes analyzing beam patterns of candidate vectors included in a predetermined candidate codebook, and eliminating at least one of the candidate vectors based on the beam patterns of the candidate vectors to generate the MU-MIMO codebook for a MU-MIMO system being comprised of the remaining vectors.