Research Article | OPEN ACCESS
Diagonal Loading of Robust General-Rank Beamformer for Direction of Arrival Mismatch
1Z.U. Khan, 2A. Naveed, 1A. Safeer and 1F. Zaman
1Department of Electronic Engineering, IIU, H-10, Islamabad, Pakistan
2School of Engineering and Applied Science, ISRA, University, Islamabad, Pakistan
Research Journal of Applied Sciences, Engineering and Technology 2013 17:4257-4263
Received: June 28, 2012 | Accepted: August 08, 2012 | Published: May 01, 2013
Abstract
This study presents a technique which utilizes the movement of the peak of the main beam towards the presumed signal direction with negative diagonal loading for robust general-rank beamformer. The main beam symmetry along presumed signal direction is improved by this movement. When desired signal is contained in the data snapshots, the conventional beamformers face the problem of performance degradation even if there is a small mismatch between the presumed and the actual signal direction. Diagonal loading is a popular technique to mitigate this problem. There is no definite criterion to find diagonal loading level. A new diagonal loading method has been proposed in the literature which utilizes the movement of the peak of main beam towards the presumed signal direction with positive diagonal loading. The proposed technique works iteratively for the selection of negative diagonal loading level to move the main beam at a position to get the beam symmetry at desired level and hence the desired robustness. The mismatched signal will not be cancelled as long as it is within the half of the width of the main beam. But there is the tradeoff between this robustness and interference cancelling capability.
Keywords:
Adaptive beamforming, Minimum Variance Distortionless Response (MVDR) beamformer, robust adaptive beamforming,
Competing interests
The authors have no competing interests.
Open Access Policy
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Copyright
The authors have no competing interests.
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ISSN (Online): 2040-7467
ISSN (Print): 2040-7459 |
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