Precoding Matrix Codebook Design for MIMO Antenna Spacing
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Solution Overview
Problem
Existing MIMO wireless communication systems face performance loss and reduced throughput due to poor matching of precoding matrices when antenna spacing is large, leading to increased inter-antenna correlation and reduced precision in channel knowledge at the transmitter.
Innovation Solution
A method for selecting a precoding matrix based on a codebook structure that accounts for phase differences between antennas, allowing for improved matching of antenna spacing conditions, thereby reducing correlation and enhancing precoding precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a codebook based on inter-antenna strong related features is used, then the codebook design is simple and consistent, but the precoding precision is reduced when antenna spacing is large
Solution Approach 1:
The codebook is designed with different local characteristics for different antenna spacing scenarios. Phase difference parameters are specifically adjusted to match local channel conditions, allowing the codebook to adapt to varying antenna spacings while maintaining manageable complexity through structured design.
Solution Approach 2:
The codebook incorporates variable phase difference parameters that can be adjusted based on antenna spacing conditions. By changing these parameters dynamically or selecting from multiple codebook configurations, the system maintains high precoding precision across different antenna spacing scenarios without requiring complete redesign of the codebook structure.
2Power
If antenna spacing is increased, then the array gain is improved, but the inter-antenna correlation decreases leading to performance loss
Solution Approach 1:
The system adjusts phase difference parameters in the codebook to compensate for changes in inter-antenna correlation caused by varying antenna spacing. This allows the transmitter to maintain accurate channel knowledge and reliable precoding even when antenna spacing is increased to achieve higher array gain.
3Quantity of substance
If existing PMI feedback method is used, then the feedback overhead is low, but the system throughput is reduced due to performance loss
Solution Approach 1:
The PMI feedback mechanism is enhanced by incorporating phase difference parameters that reflect actual antenna spacing conditions. This allows more accurate precoding matrix selection without significantly increasing feedback overhead, thereby improving system throughput while maintaining efficient feedback utilization.
Data Source
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AI summary
The present invention provides a method for feeding back a precoding matrix indicator, a receive end and a transmit end, where the method includes: selecting, by a receive end, a precoding matrix W from a codebook based on a reference signal, where W∈X1θ1X2θ2ϕn, the θ1 and the θ2 indicate a phase difference of weighted values for signal transmission between two neighboring antennas in a first antenna group of a transmit end and a phase difference of weighted values for signal transmission between two neighboring antennas in a second antenna group of the transmit end, where the signal transmission between the two neighboring antennas in the first antenna group and the signal transmission between the two neighboring antennas in the second antenna group are for a same transmission layer, the ϕn indicates a phase difference of weighted values for signal transmission between the first antenna group and the second antenna group, where the signal transmission between the first antenna group and the second antenna group is for a same transmission layer, ϕn=ej2πnM, M is a positive integer, n is a non-negative integer less than M, θ1 and θ2 of at least one precoding matrix in the codebook are different, and the first antenna group and the second antenna group belong to a same multi-antenna system; and sending, by the receive end, a precoding matrix indicator PMI to the transmit end. In this way, a weak correlation between antennas can be ensured, and the precoding precision can be effectively improved, thereby reducing the performance loss, and improving the system throughput.