Adaptive Broadband Beamforming with Robust Capabilities under Nonideal Environments
Date Issued
2009
Date
2009
Author(s)
Wang, Cheng - Chih
Abstract
To date, adaptive antenna array has played an important role in communication systems. Broadband beamformer , such as the DFT beamformer, supplies good properties of receiving broadband signals, and it can suppress interference and noise to get a high “Output SINR ”. But, the performance of the broadband beamformer may be highly degraded if there are some non-ideal factors .The mismatch between the directional vectors of the signal and the steering vectors in the receiver, array position perturbations and the coherent interference effect are the non-ideal factors that we consider in the thesis .We concentrate on amending the influence for the non-ideal factors one after another with the DFT beamformer .n this thesis, we mainly use noise-subspace projection method including the eigen-decomposion of spectral density matrix and a gradient method to iteratively renew to correct the problems of the mismatch between the directional vectors of the signal and the steering vectors in the receiver as well as the array position perturbations. Finally, we compare the results by using the noise-subspace projection method and variable loading. To confront the coherent interference, first, we exploit the estimates of coherent interference incident directions, and then use the information to transfer received data to another space so as to eliminate the coherent interference. And then two methods, namely DMV and SMV, are used to find the optimal weight vectors, respectively according to LCMV criterion in the transform domain. Ultimately, we compare the performance between DMV and SMV.
Subjects
Broadband Beamforming
Nonideal Environments
Type
thesis
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