Robust Beamforming via Virtual Antenna Null Broadening
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Solution Overview
Problem
Wireless communication systems with a limited number of antenna elements face challenges in generating broad nulls to effectively mitigate co-channel interference, as narrow nulls are sensitive to calibration errors and user movement, leading to reduced interference cancellation performance.
Innovation Solution
The system employs an augmented virtual antenna array with additional elements to conceptually broaden nulls, allowing for greater noise immunity and adaptability to errors in interferer position, with the virtual weights transformed back to physical antenna elements to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If narrow nulls are used in beamforming with limited antenna elements, then interference cancellation performance is improved when interferer position is accurately known, but the system becomes highly sensitive to calibration errors and user movement, causing performance degradation
Solution Approach 1:
The patent extends the physical antenna array into a virtual extended array by adding virtual antenna elements beyond the physical boundaries. This dimensional extension allows the formation of broader nulls that are less sensitive to interferer position errors while maintaining interference cancellation capability, effectively resolving the contradiction between narrow null precision and robustness to calibration errors.
Solution Approach 2:
The patent creates virtual copies of physical antenna elements to form an extended array. These virtual elements are mathematical constructs that replicate the response characteristics of physical elements, enabling the system to achieve broader nulls without adding physical hardware. This copying approach maintains interference rejection while improving robustness to position errors.
2Reliability
If the number of physical antenna elements is increased to broaden nulls and improve robustness, then sensitivity to calibration errors and user movement is reduced, but system cost and complexity increase
Solution Approach 1:
The patent uses virtual copies of antenna elements to achieve the effects of having more physical elements. These virtual elements are implemented through signal processing rather than physical hardware, allowing the system to obtain broader nulls and improved robustness without increasing the actual number of antenna elements, thus avoiding increased cost and physical complexity.
Solution Approach 2:
The patent replaces the mechanical approach of adding more physical antenna elements with a signal processing approach using virtual array elements. Instead of physically expanding the antenna array to achieve broader nulls, the system uses mathematical transformations and signal processing techniques to create the equivalent effect, thereby avoiding the cost and complexity of additional hardware.
Data Source
AI summary
A method and system for generating beamforming weights for a plurality of antenna elements is disclosed. The invention consists of generating broadened nulls in a direction of arrival corresponding to one or more co-channel interference signals. The broadened nulls permit deviations in the measurement of the direction of arrival or variations therein. The increased information content inherent in generating the broadened nulls is accommodated by postulating the existence of a virtual augmented antenna array comprising the antenna elements of the physical array and a plurality of additional virtual elements. The beamforming weights for the elements of the augmented array are truncated down prior to translation to the size of the physical array and are applied to create the desired broadened nulls and thereby improve system performance.