OL SU-MIMO Codebook Subset Selection in MIMO Systems
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Solution Overview
Problem
In MIMO communication systems, there is a need for an apparatus and method to generate a codebook for Open-Loop-MIMO (OL-MIMO) from a codebook used in Closed-Loop-MIMO (CL-MIMO) systems, especially in time-varying channel environments where channel information feedback is challenging, and the selection of a precoding matrix for OL-MIMO is unclear.
Innovation Solution
A method and apparatus for generating a downlink Open-Loop Single User MIMO (OL SU-MIMO) codebook subset within a base codebook based on feedback information, optimizing it for spatial diversity and opportunistic scheduling, and applying it for data transmission using a precoding unit, while ensuring the nested property for resource allocation and rank adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a codebook for Closed-Loop-MIMO is reused for Open-Loop-MIMO transmission, then the same codebook structure can be utilized, but the method for selecting a precoding matrix becomes unclear without channel matrix feedback
Solution Approach 1:
The terminal performs self-service by autonomously selecting a precoding matrix from the codebook based on channel quality metrics without requiring explicit channel matrix feedback from the terminal to the base station. The base station also performs self-service by determining codebook subsets based on terminal feedback information, enabling independent operation in open-loop mode
Solution Approach 2:
The system changes the operational parameters by transitioning from closed-loop to open-loop mode, where the terminal uses channel quality indicators and other feedback information to select precoding matrices from predefined codebook subsets, rather than feeding back detailed channel matrix information
2Productivity
If codebook subsets are optimized for spatial diversity and opportunistic scheduling, then communication efficiency improves, but system complexity increases
Solution Approach 1:
Codebook subsets are predetermined and configured in advance based on spatial diversity and opportunistic scheduling requirements. The base station prepares multiple codebook subsets with different properties beforehand, allowing efficient selection during operation without real-time optimization complexity
Solution Approach 2:
The codebook is segmented into multiple codebook subsets, each optimized for different transmission scenarios such as spatial diversity or opportunistic scheduling. This segmentation allows the system to select appropriate subsets based on channel conditions without managing the entire codebook at once, reducing operational complexity
Data Source
AI summary
A transmission/reception apparatus and a method thereof in a codebook-based multiple antenna system is provided. In a transmission method in a codebook-based Multiple Input Multiple Output (MIMO) system, feedback information is received from a receiver. A downlink Open-Loop Single User MIMO (OL SU-MIMO) codebook subset is determined within a base cookbook based on the feedback information. At least one data stream is transmitted via at least one antenna using the determined downlink OL SU-MIMO codebook subset.