Block Diagonal Precoding Matrix for Cross-Polarized MIMO
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Solution Overview
Problem
Existing multi-antenna transmission systems using cross-polarized antenna arrays face inefficiencies due to channel designs tailored for equal powered channel coefficients, which do not accurately represent the block diagonal structure of cross-polarized channels, leading to suboptimal performance in MIMO systems.
Innovation Solution
The method involves determining and using a precoding matrix with a block diagonal structure to adapt multi-antenna transmissions, matching the characteristics of the effective channel, thereby improving radio link performance by optimizing power allocation and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If codebook size is increased to improve channel matching accuracy, then performance under cross-polarized antenna arrays is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The codebook is segmented into two separate codebooks: a first codebook for determining the block diagonal structure parameters (block sizes and powers) and a second codebook for determining the precoding vectors within each block. This segmentation allows the system to maintain accurate channel matching for cross-polarized antenna arrays while reducing the overall signaling overhead by separating the structure determination from the precoder selection.
Solution Approach 2:
The block diagonal structure parameters (block sizes and relative powers) are extracted as separate signaling elements from the traditional precoder codebook. By taking out these structural parameters and signaling them separately, the system can accurately represent the cross-polarized channel characteristics without requiring an excessively large codebook, thus reducing signaling overhead while maintaining matching accuracy.
2Device complexity
If traditional precoding methods are used for cross-polarized antenna arrays, then system complexity is maintained, but transmission performance deteriorates due to mismatched channel models
Solution Approach 1:
The precoding approach applies local quality by treating different blocks in the MIMO channel differently according to their specific characteristics. Each block corresponds to a specific polarization group with distinct channel properties, and the precoder is designed to optimize performance for each block individually rather than applying a uniform precoding strategy across all antennas, thus improving transmission performance for cross-polarized arrays.
Solution Approach 2:
The invention changes the parameters used to describe the channel structure by introducing block diagonal structure parameters (block sizes and relative powers) that specifically capture the characteristics of cross-polarized antenna arrays. By changing from traditional uniform channel modeling to block diagonal structure modeling, the system achieves better transmission performance while maintaining manageable system complexity through structured parameterization.
Data Source
AI summary
An objective problem of the invention is to provide a mechanism for improving the performance of a radio access network. According to a first aspect of the present invention, the object is achieved by a method in a first node for adapting a multi-antenna transmission to a second node over an effective channel. The first node and the second node are comprised in a wireless communication system. The method comprises the steps of obtaining at least one symbol stream and determining a precoding matrix having a block diagonal structure. The method comprises the further steps of precoding the at least one symbol stream with the determined precoding matrix, and transmitting the at least one precoded symbol stream over the effective channel to the second node.