SC-MIMO Equalization Direction Switching for Non-Minimum Phase Channels
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Solution Overview
Problem
Existing wireless communication systems using time domain linear equalization units for SC-MIMO transmission face instability and divergence issues when dealing with non-minimum phase transfer functions, leading to ineffective suppression of inter-antenna and inter-symbol interference.
Innovation Solution
The system determines whether the transfer function of the equalization unit is minimum or non-minimum phase and adjusts the equalization direction accordingly, using an adjugate matrix and inverse determinant of the transfer function matrix to perform forward or inverse direction equalization, thereby stabilizing the operation even in cases of non-minimum phase transfer functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inverse matrix H−1(z) of a transfer function matrix H(z) is used for a transfer function of a linear equalization unit, then equalization of inter-antenna interference and inter-symbol interference can be achieved, but the operation becomes unstable and the impulse response diverges when a part of the transfer function becomes non-minimum phase
Solution Approach 1:
The patent applies inversion by switching the equalization direction based on the phase characteristics. When the determinant of the transfer function matrix is determined to be non-minimum phase, the system performs inverse direction equalization instead of forward direction equalization. This inversion of the equalization approach allows the system to handle non-minimum phase transfer functions that would otherwise cause instability and divergence, thereby resolving the contradiction between maintaining stability and expanding applicability.
2Reliability
If forward direction equalization is performed, then stable operation is achieved for minimum phase transfer functions, but the system cannot handle non-minimum phase transfer functions
Solution Approach 1:
The patent implements dynamics by making the equalization direction adjustable based on the phase characteristics of the transfer function. The system dynamically determines whether to perform forward or inverse direction equalization by evaluating the determinant of the transfer function matrix. This dynamic adaptation allows the system to maintain stable operation for minimum phase transfer functions while also being capable of handling non-minimum phase transfer functions, thus resolving the contradiction between stability and versatility.
3Device complexity
If the equalization direction is fixed, then the system structure is simple, but the system cannot adapt to different phase characteristics of transfer functions
Solution Approach 1:
The patent applies parameter changes by modifying the equalization direction parameter based on the phase characteristics of the transfer function. The system calculates the determinant of the transfer function matrix and changes the equalization direction parameter accordingly - using forward direction for minimum phase and inverse direction for non-minimum phase. This parameter-based adaptation allows the system to handle different phase characteristics without requiring fundamentally different structural designs, thus resolving the contradiction between simplicity and adaptability.
Data Source
AI summary
A transmitting station apparatus includes a training signal generation unit, a transmission end linear equalization unit configured to equalize data signals by a transmission end transfer function, and a transmitting station communication unit configured to transmit a training signal or a plurality of data signals and receive information of the transmission end transfer function from a receiving station apparatus. The receiving station apparatus includes a communication path estimation unit configured to estimate a communication path response from the training signal, a reception end coefficient calculation unit configured to calculate the transmission end transfer function with an adjugate matrix of a transfer function matrix H of the communication path response as a transfer function and a reception end transfer function with an inverse of a determinant of the transfer function matrix H as a transfer function, and a reception end linear equalization unit configured to equalize reception signals by using the reception end transfer function. The reception end linear equalization unit determines whether the determinant of the transfer function matrix H is a minimum phase, performs a forward direction equalization in a case of the minimum phase, and performs an inverse direction equalization in a case of a non-minimum phase.