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14 views

Difference between single layer and dual layer beamforming in LTE

I'm trying to understand the difference between single and dual layer beamforming in LTE as described in TS 36.101 section B.4.1 and B.4.2 respectively. Also refer to TS 36.211 section 6.3.4.2.3 for ...
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1answer
20 views

Calculating covariance matrix for MVDR beamforming

I am trying to calculate the covariance matrix that is required for the calculation of an MVDR beamformer. I am getting confused as to how to calculate it. I have an array of 3 microphones each with a ...
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2answers
75 views

Intuitive interpretation of Fourier transform in beamforming

When applying Fourier transform in time domain the signal will be carried to frequency domain. And when we apply Fourier transform in spatial domain the signal will be carried to directivity domain. ...
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0answers
13 views

Beamformer IDFT Weight Vector Determination algorithm weight vector is bigger than microphone count

I am implementing Beamformer IDFT Weight Vector Determination algorithm which can be found page 124 of Optimum Array Processing (google preview) book. My goal is to filter a 1500Hz signal which is ...
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2answers
179 views

Can a narrowband beamformer be used for speech separation

In my master thesis I am trying to implement a beamformer. I've already done the delay-sum part 1 year ago. I have been told: in FIR filtering we can do FFT --> null the unwanted frequency bin --> ...
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24 views

Precoding Matrix for LTE transmission mode 9

I'm looking at 3GPP document 36.101 v12 section B.4.3 which describes the Generic beamforming model. $W(i)$ the precoding matrix is defined as a matrix of size $N_{CSI} \times v$, with $N_{CSI}$ being ...
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0answers
50 views

Best beamforming algorithm for audio cocktail party

I have read some texts about different types of beamformers. They all seem to have pros and cons. So I was trying to figure out which type of beamformer to implement, when the goal is to get best ...
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0answers
37 views

How to think about beamforming when there's no “space” between receivers?

I'm trying to wrap my head around how does "beamforming" work when there's no physical "space" between receivers. My background knowledge: I've always thought about beamforming as a sort of spacial ...
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22 views

1D Microphone Array Performance in radius domain

In angle of arrival Microphone array's gain is good enough . But I am curious about microphone array's gain in the radius direction. I know microphone arrays can focus in to radius direction like ...
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0answers
27 views

The Rank Of Broadband LCMV Beamformer Constraint Matrix

So I am wondering why I keep seeing that the rank of the LCMV Broadband Constraint Matrix is equal to the number of constraints, when in practice, I find that the rank is only 1. This is precluding me ...
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1answer
66 views

IFFT of Microphone Array Directivity Responce

I am implementing a microphone array simulation in my thesis. My prof and many documents indicates that microphone array behaves like filters in DSP but instead time-frequency domain there exists ...
4
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1answer
107 views

Calculating Beam pattern, Directivity of microphone array

As answered in Relationship of Fourier Transform and Spatial Directivity Pattern the relation between directivity pattern and weights is given. But I am bit confused, I have Beamformer weights ...
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0answers
33 views

Mean of the product of a signal with its conjugate

I have to find $E\{s_m\cdot s_n^*\}$, where $E$ denotes mean or expected value; $s$ is a signal at $m \in [1\ldots M]$ elements and $^*$ denotes its conjugate. I am doing it by dividing it into two ...
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1answer
151 views

Plotting antenna pattern in MATLAB

I have a beamformed output, say y = weights * signal, where the signal is gaussian,i.e signal = randn( 1 , 1e5 ). Now I want ...
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0answers
27 views

Understanting reference signal on Beamforming

Algorithms such as Minimum Mean Square error and Least Mean-Square use a reference signal. The weigth vectors are defined by minimizing the error between the array output and the reference. I don't ...
0
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1answer
35 views

Beamforming with directional sensors

Having photo-diodes with a very narrow field of view (+-10 degrees for half power) what should I consider when designing a beam-forming algorithm? I know that I could use many photo-diodes mounted in ...
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0answers
105 views

Which algorithms one can use for matrix inversion (for beamforming application MVDR/LCMV) in Fixed Point?

I have implemented beamformer(MVDR/LCMV) for speech enhancement in matlab, now I am trying to convert it to fixed point implementation. during the weight calculation step correlation matrix inversion ...
2
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2answers
164 views

Relationship of Fourier Transform and Spatial Directivity Pattern

I am reading over and over the Section 1.2 of most understandable mic array tutorial for me . A sound wave is dependent on time and space which can be observed in the great link. But I can't ...
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1answer
217 views

Directivity Pattern of microphone array

Directivity pattern of a microphone array is fourier transfrom of microphone weight values. By modifying the amplitude weights, we can modify the shape of the directivity pattern. I can really see ...
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1answer
80 views

Microphone Array null steering unexpected results after IFFT

I am writing an open source microphone array simulation program:SharpEar. When I give uniform weight to microphone array elements, the result in the angle is a sinc function as expected. There are 41 ...
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1answer
65 views

Auto/cross correlation of a cosine in the context of an adaptive beamformer

I am currently reading chapter 13 of 'Adaptive Signal Processing' by Widrow and Stearns, so if anyone happens to have a copy of the book to hand it could be helpful. I am reading the chapter on ...
0
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1answer
131 views

use of complex conjugate of weight vectors in beamforming literature

in beamforming literature, people generally quote the following as a starting point: $y(k) = \sum_{i} w_i^*\cdot x_i(k)$ Here: i varies from 1 to N where N is the number of sensors $w_i^*$ is the ...
4
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1answer
173 views

Is it possible to do further beamforming on already beamformed data?

I've a circular array of eight FM antennas. I'm doing digital beamforming to form eight beams with the following beam patterns: The objective is to reduce my side lobes even further, and to get ...
8
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2answers
240 views

practical wideband digital beamforming for large arrays in radar applications

I do understand the mathematics behind digital beamforming but I am not sure how such systems are practically implemented. For example, in a typical wideband FMCW radar operating in S-band, the ...
3
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0answers
146 views

Question on spatial sampling for non-linear and/or non-uniform arrays

I am a little confused as to how to compute the nyquist criterion for a sensor array that is not linear, and/or non-uniform. For the linear, uniformly spaced case, the spatial nyquist is delimited by ...
7
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1answer
888 views

Difference between 'conventional' and 'adaptive' beamformers?

This might be a terminology question but I am not sure. Basically, what is the difference between conventional beamformers, and adaptive beamformers? I thought that all beamformers were inherently ...