Adaptive Array Weight Update for Signal Cancellation
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Solution Overview
Problem
Existing adaptive array systems face challenges in efficiently eliminating interference signals without requiring additional hardware or increasing computational complexity, particularly when interference signals partially or completely correlate with the original signal, leading to signal cancellation and reduced estimation performance.
Innovation Solution
The Alternate Mainbeam Nulling (AMN) algorithm is employed, which alternately updates array weights using unit gain and null constraints in a linearly constrained least mean square (LMS) algorithm, reducing signal cancellation by maintaining orthogonality to the original signal direction and improving estimation performance without additional hardware or elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linearly constrained adaptive array processor algorithm is used to estimate the original signal, then the interference signal can be fully estimated without distortion when it does not correlate with the original signal, but when the interference signal partially or completely correlates with the original signal, the original signal may be partially or completely eliminated
Solution Approach 1:
The patent employs dynamic switching between different adaptive processing modes (constrained and unconstrained) based on the correlation level between interference and original signals. The system adaptively adjusts the constraint application to prevent signal cancellation while maintaining estimation accuracy, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent changes the constraint parameter (unit gain constraint) dynamically based on signal correlation conditions. When interference correlates with the original signal, the constraint is adjusted or removed to prevent cancellation, while maintaining the ability to estimate signals accurately when correlation is low.
2Reliability
If a master-slave type array processor is used to prevent signal cancellation, then the original signal can be protected from cancellation, but an additional array processor is required and the number of computations is large
Solution Approach 1:
The patent merges the functions of master and slave processors into a single array processor by implementing both constrained and unconstrained processing paths within one device. This integration eliminates the need for separate processors while maintaining signal cancellation prevention capabilities, reducing device complexity.
Solution Approach 2:
The single array processor is designed to perform multiple functions: it can operate in constrained mode to prevent signal cancellation, in unconstrained mode for efficient processing, and switch between modes as needed. This multi-functionality replaces the specialized master-slave configuration with a universal processor.
3Measurement precision
If spatial smoothing approach method is used to prevent signal cancellation, then coherent interference can be efficiently eliminated, but as the number of interference signals increases, the number of subarrays must be increased requiring more elements
Solution Approach 1:
The patent applies spatial smoothing selectively rather than to all subarrays simultaneously. By applying the smoothing technique partially or in a controlled manner, the system achieves effective interference elimination without requiring a proportional increase in the number of array elements, thus resolving the contradiction between elimination efficiency and element quantity.
4Object-affected harmful factors
If conventional adaptive processing is used to eliminate interference signals, then interference can be reduced, but the original signal may be partially or completely eliminated by correlation between the original signal and the interference signal
Solution Approach 1:
The patent applies preliminary constraints to prevent the harmful correlation effect before it can eliminate the original signal. By pre-establishing unit gain constraints in the signal direction and using predictive algorithms to anticipate correlation issues, the system prevents signal cancellation while still achieving interference elimination through subsequent adaptive processing.
Data Source
AI summary
The present invention relates to an interference eliminating method in an adaptive array system, and an array processing device using the interference eliminating method. A predetermined array weight is applied to signals input through respective array elements, and the respective input signals to which the array weight is applied are added to generate an array output signal. Subsequently, the array weight is updated based on the array output signal and a first convergence parameter for unit gain constraint, and the array weight is updated based on the array output signal and a second convergence parameter for null constraint. Since a process for generating the array output signal is repeatedly performed based on the updated array weight, an interference signal is eliminated from the input signal.