Superdirective Antenna Array Precoding for Spectral Efficiency
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Solution Overview
Problem
Conventional multi-user beamforming solutions fail to improve system spectral efficiency due to the inability to leverage the coupling effect between antennas in superdirective antenna arrays, leading to reduced array gain and system capacity in compact arrays.
Innovation Solution
A superdirective antenna array multi-user precoding method is developed, which constructs a unitary matrix to account for antenna coupling, incorporating regularization matrices to address ohmic loss and channel estimation errors, and calculates precoding matrices that optimize signal processing to enhance spectral efficiency and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multi-user beamforming solutions are used, then the system can operate with compact arrays, but the spectral efficiency is not improved due to inability to achieve superdirectivity
Solution Approach 1:
The patent changes the antenna spacing parameter from conventional half-wavelength to ultra-close spacing (much less than half-wavelength), enabling superdirectivity. This parameter change transforms the array from a conventional configuration to a superdirective configuration, achieving M2 scaling of array gain and significantly improving spectral efficiency in multi-user MIMO systems.
Solution Approach 2:
The patent introduces dynamic precoding strategies that adapt to the coupling effects in superdirective arrays. By using unitary matrices and regularization techniques, the system dynamically adjusts the precoding vectors to maximize spectral efficiency while managing the complex interactions between closely-spaced antennas.
2Power
If antenna spacing is reduced to achieve superdirectivity, then array gain is improved proportionally to M2, but mutual coupling between antennas increases
Solution Approach 1:
The patent converts the harmful mutual coupling effect into a beneficial resource for superdirectivity. By deliberately designing ultra-close antenna spacing, the strong coupling between antennas is harnessed to achieve M2 scaling of array gain. The coupling that was previously considered harmful becomes the mechanism enabling superdirectivity and improved spectral efficiency.
Solution Approach 2:
The patent changes the antenna spacing parameter to ultra-close values, transforming the coupling effect from harmful to useful. This parameter change enables the system to exploit mutual coupling for achieving superdirectivity, where the coupling coefficient becomes a design parameter rather than a limitation.
3Productivity
If ultra-dense antenna arrays are deployed to improve system throughput, then spectral efficiency can be enhanced, but deployment difficulty increases on fixed-size antenna panels
Solution Approach 1:
The patent segments the antenna array into a modular MxN configuration that can be deployed on fixed-size panels. By using ultra-close spacing within each module and applying superdirective beamforming techniques, the system achieves high throughput without requiring excessively large physical panels. The segmented approach allows practical deployment while maintaining the theoretical benefits of ultra-dense arrays.
Data Source
AI summary
A superdirective antenna array multi-user precoding method, a device, and a medium belonging to the field of wireless communication are provided. The method includes: constructing a unitary matrix U ∈ CM×M for terminal users U, last N(N≤K−1) columns of the unitary matrix U being an orthonormal basis of the interfering user channel space span {hi,i=1, . . . ,K,i≠u} respectively, where N is a dimension of the interfering user channel space, M is the total number of antennas on a network device side, K is the total number of terminal users communicating, and M≥K is satisfied; intercepting the first M−N rows of a matrix UHhu to obtain a matrix ηu, where ηu ∈ C(M−N)×1, hu represents channel state information of the uth terminal user, and the superscript H represents a conjugate transpose; intercepting first M−N rows and first M−N columns of a matrix UHZU to obtain a matrix , where ∈ C(M−N)×(M−N) a matrix Z ∈CM×M, elements in Z represent coupling coefficients of any two antennas; calculating a precoding matrix au=Uau=U(αu0)of the uth terminal user, where αu=−1ηu*.