Questions tagged [mimo]
The mimo tag has no usage guidance.
30
questions
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1answer
21 views
Basic in “Precoding and Equalization Schemes”
I have found the interesting following paper for me:
SVD-based MIMO Precoding and Equalization Schemesfor Realistic Channel Knowledge: Design Criteria and Performance Evaluation
The paper is old, ...
0
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1answer
45 views
Frequency-selective channel: Basic in theory
In a lecture, it was covered a topic "frequency selective and flat fading channel models".
For case, the frequency selective channel we have a channel impulse response ...
0
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0answers
17 views
performance analysis of channel
I am studying channel precoding, and as HW lab it was given a task to implement a system with different precoding algorithms and to apply an algorithm that was given in lab description. So I have ...
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0answers
14 views
Use of moment generating function (MGF) approach for driving closed form expression of pairwise error probability (PEP) of space-time code
i am trying to evaluate the performance of a multi-antenna communication system that uses space-time coding. To do so, i would need to derive a closed form expression for the pairwise error ...
0
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1answer
11 views
pairwise error probability and union bound of space time code
i have a question that might seem silly.
For a given space time code, say a constellation of 16 unitary matrices. When using the union bound to derive an upper bound on the average error probability (...
1
vote
1answer
27 views
Employing MIMO under the two-ray propagation model
I'm a little confused about how 'rich' the scattering environment should be for MIMO to work (i.e. for the channel matrix to be full rank). For instance, let's say we have a Tx and Rx with two ...
0
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1answer
28 views
Understanding the concept of semi-blind receivers
In the book "Signals and Images: Advances and Results in Speech, Estimation, Compression... ", an overview of using tensor analysis in signal processing is given. On page 243 it is explained that an ...
0
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1answer
24 views
STBC Rank Criteria Explanation
I am learning about space-time block coding and I am trying to understand why the rank criteria is a good measure of diversity gain. I know that we want to maximize the distance between codewords $X_i,...
1
vote
3answers
59 views
Explanation a flat fading channel in case MIMO OFDM
I am trying to understand flat fading and frequency selective channels.
As I understood, in the case of flat fading channels MIMO channel elements, $h_{i,j}$, are random variables.
Which assumption ...
0
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1answer
20 views
BER performance of a space-time code over Rayleigh channel model
For a given space-time code, and in general terms, how would one proceed in the evaluation of the BER performance of this code ?
In order to be more clear, say i have 16 code matrices(who's elements ...
1
vote
2answers
38 views
Dimension of Matrix in MIMO with multi-path
In a MIMO system, the received signal is supposed to be $y = Hx + n$, where $H$ is the channel of dimension $N_t \times N_r$, $x$ is the transmitted signal with dimension of $N_t\times 1$ , and $n$ is ...
1
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1answer
52 views
Is it possible to use MRC with DS-CDMA-MIMO [closed]
I'm wondering how to use the Maximum Ratio Combining with MIMO-DS-CDMA, I have used the MIMO with DS-CDMA using Walsh code, then at receiver I couldn't recover the transmit signal using the MRC. here ...
0
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1answer
34 views
Possibility of using Power allocation with Maximum likelihood estimation
I have a basic question about maximum likelihood (ML) estimator and its implementation with power allocation.
Suppose we are using $MIMO$ system with $4$x$4$ transmit and receive antennas, so the ...
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0answers
15 views
guard interval calculation for multi-cell massive MIMO
I am interested in a multi-call massive-MIMO system modeled as in the works of T. Marzetta, for example:
"Inter-Cell Interference in Noncooperative TDD Large Scale Antenna Systems".
In these works, ...
0
votes
1answer
27 views
How multi layer map to different beams in LTE Beamforming
I understand for SU-MIMO Beamforming single layer maps to all antennas with phase shift applied to create beam. Also I understand in this case all beams will be carrying same signal (say s1).
But in ...
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0answers
106 views
Working principal of MIMO(2 by 2)-OFDM (802.11n)
I have gained basic knowledge on MIMO-OFDM from online sources and in process of building 802.11n standard in GnuRadio+USRP B210. My goal is to analyze the channel state information and play with it ...
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0answers
60 views
Region of convergence for discrete system
I am confused by two questions on the region of convergence (ROC) when applying the $Z$-transform.
Consider a discrete-time linear system $$x[n+1] = Ax[n]+Bu[n], \qquad y[n]=Cx[n]+D$$ whose transfer ...
0
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1answer
105 views
Channel model: LOS Component and Rician K-factor
I am asking about Rician K- Factor in this model:
I know that if $K=0$ then it is a pure Rayleigh fading, if $K= \infty$, then non fading Channel.
What is it, if $0<K<\infty$ ?
If i represet ...
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0answers
38 views
On $H_\infty$ norm for transfer function
For a given scenario in the context of control system, I'm trying to investigate how the $H_\infty$ norm can be calculated for a transfer function as follows:
$$G(s)= \frac{w_n^2}{s^2 +2\zeta w_ns +...
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0answers
75 views
On the transmit weight vector in MIMO-MRC systems
Recently, I am reading paper [1]. In this paper, the author wrote:
In MIMO-MRC systems in the absence of interferers, the signal vector at the received $n_R$ antennas is given by
$$\mathbf{r} = \...
0
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1answer
77 views
Using MIMO with DS-CDMA and spread spectrum
I have a question about using MIMO with DS-CDMA. suppose we are using 4 TX antennas, and 4 RX antennas, then the Reyleigh ...
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0answers
50 views
FMCW MIMO radar RX post processing pipe
Currently working on a FMCW MIMO radar RX pipe consisting of the following modules:
2D CFAR – processing the Range Doppler images per Angle.
3D clustering – clustering the 3D cube generated from the ...
0
votes
2answers
94 views
MU-MIMO Sensitivity to Line of Sight (LOS)
Why do researchers talk about MU-MIMO being "less sensitive to line of sight" / "LOS Okay"? For example in this video, time=[00:40,00:42]
Similarly, "User separation based on spatial channel ...
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1answer
44 views
Channel direction
I am reading a book called Massive MIMO Networks: Spectral, Energy, and Hardware Efficiency, and it implies that $$\frac{\mathbf{h}}{\sqrt{\text{E}\left\{\|\mathbf{h}\|^2\right\}}}$$ is the channel ...
0
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1answer
195 views
What is the index modulation in OFDM and Subcarrier Index modulation?
I'm new here, I'd like to ask about the OFDM-IM (OFDM - Index modulation), what is it and how it works? Is it the same as SIM-OFDM?
I checked white papers, I see it's using the index of sub-...
0
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1answer
283 views
Use of Long Training Field (LTF) of 802.11 standard
In 802.11a/n the preamble part has L-LTF(Legacy-Long Training Field) and HT-LTF(High Throughput-Long Training Field). I want to clarify my understanding of these two fields:
Are the only difference ...
0
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1answer
62 views
Why Isn't the ML Estimator (MLE) in MIMO Spatial Multiplexing Obtained by the Least Squares Solution?
In the simplest scenario of MIMO spatial multiplexing: $$\mathbf{y} = H\mathbf{s} + \mathbf{n}$$
where: $\mathbf{s}=[s_0,s_1,...s_{M-1}] \\\mathbf{y}=[y_0,y_1,...y_{N-1}]$
$\mathbf{n}=[n_0,n_1,......
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2answers
270 views
DOA - 1D Music Algorithm
I am currently working on a MUSIC algorithm for DOA of RF emitters in 3D.
At the first stage, interested to apply the 1D MUSIC using a linear array of 4 antennas, and estimate only the azimuth of the ...
2
votes
2answers
109 views
How to solve equations for the MMSE receiver?
Given the following equations for the achievable rate of the Minimum Mean-Squared Error Receiver [1]:
$$\mu = \frac{1}{K-1} \sum_{i=1, i \neq k}^{K}{\frac{1}{Mpd_{i}\left(1 - \frac{K-1}{M}+ \frac{K-1}...
0
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2answers
167 views
Problem with Convolution in MIMO System
For a flat fading channel (SISO system) we have:
$y=h \star s+n$
But for a mimo system, we have:
$y=Hx+n$ with $H \in \mathbb{C}^{N_r \times N_t}$
Why is there not the product of convolution for a ...
