Questions tagged [channel-estimation]
The channel-estimation tag has no usage guidance.
48
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Delay-doppler analysis of channel resource grid
Suppose i have a 5G NR channel resource grid or perfect channel estimate(H_grid) with 14 OFDM symbols and 1272 subcarriers. Now, after taking 2D fft of H_grid, i want to estimate doppler and delay ...
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Time-domain channel estimation using identical guard interval vectors
Assuming we have the received signal
$y = h * x $
where $*$ is circular convolution, $x$ is the transmitted signal, $y$ is the received signal and $h$ is frequency selective channel. The signal $x$ is ...
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In reality, how does channel estimation for multi-user work?
At BS, for antenna $m$, I see some papers and some code that presents the received signal $Y_{nm}$ from user $n$ as a $K \times N_{\text{symbol}}$ matrix ($K$ is the number of subcarriers, $N_{\text{...
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Radar Signal Modelling based on Channel Estimation
I am a newcomer to digital signal processing. Recently, I have been interested in this question: If we model a reflected radar signal from a target as
$$y(t)=h \ast x(t) + n(t),$$
where $h$ is a ...
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Eigen Beamforming: Explanation [closed]
It's been a few days that I have been searching the term eigen beamforming, but still haven't get any satisfactory literature reference. It would be great if you could give any details or point to any ...
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Obtaining perfect channel estimates in simulated channel estimation
In SISO systems of OFDM, I am interested in applying deep learning for channel estimation, but I am unsure of how to obtain perfect channel estimation as the label in simulations. If you have any ...
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66
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QPSK Channel Detection Algorithm
I send a QPSK signal over pluto sdr and receive it from rtlsdr. As you can see from the screenshot below SNR of the received signal is very high, and the signal is very distinguishable. Hence, it is ...
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LTE PSS Channel Estimation for coarse SSS Equalization
In LTE the Primary Synchronisation Signal (PSS) can be detected by taking a correlation with the known 3 zadoff chu sequences (roots: 25,29,34). Once the peak has been detected the receiver knows ...
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Calculation of the LMMSE Channel Estimator
Consider a MIMO system equipped with $N_t$ transmit antennas and $N_r$ receive antennas.
The received signal over $L$ snapshots are given by
$$Y = H X + Z,$$
where $X$ is the $N_t \times L$ transmited ...
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201
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5G strandard pilot allocation, channel estimation method
I'm trying to create an OFDM simulation, but I don't know the 5G standard pilot allocation estimation method.
Is this simulation good?
One transmission unit has $64$ subcarriers and $14$ OFDM symbols. ...
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Numerical Stability for Channel Estimation
In this post:
Compensating Loudspeaker frequency response in an audio signal
I derive the Wiener-Hopf equations for least squares equalization (and channel estimation if we swap Tx and Rx) from the ...
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Fractionally spaced equalizer using LMS algorithm
I am doing a project about the fractionally spaced equalizers on matlab. The goal is to mitigate ISI on the signal using the LMS algorithm to update the tap weights of the FSE. Below i have uploaded ...
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fractionally spaced channel equalizer code [closed]
I want to write a program in matlab for an adaptive fractionally spaced equalizer with lms algorithm.consider each packet with 150 bits that 25 first bits are pilot and used to train weights of the ...
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Perfect channel estimation for OFDM (via H=Y/X) in MATLAB
Despite using the same channel for convolution, each time I get a different estimated channel. Could you please tell me what I'm doing wrong? I want to demonstrate that I can estimate the same channel ...
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Least Squares Solution Using the DFT vs Wiener-Hopf Equations
Least Squares channel estimation (or equalization) can be accomplished using the "Wiener Hopf Equations", or the Discrete Fourier Transform. Both appear to be least squares solutions. How do ...
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How can we measure the accuracy of channel estimation?
Suppose I have a channel matrix $\mathbf{H}$ and I estimate it as $\mathbf{\hat{H}}$. How can I measure the accuracy of the estimate? Is using the $\mathtt{MSE}=\mathbb{E}\left\{\|\mathbf{H}-\mathbf{\...
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OFDM channel estimation using the transmitted signal multiplied with a matrix
I have OFDM system, where the modulated signal $x$ with length $N$, and $N$ is the number of subcarriers in OFDM symbol. $x$ is multiplied with a well-known unitary matrix $G \in N \times N$ before ...
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Should we use Maximal ratio combining and an equalizer together?
I have confusion on MRC(Maximal Ratio Combining) method which I would like to clarify. An example is where I have 1 transmit antenna and 4 receive antennas. The concept of MRC is to combine all the ...
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Is there any sampling offset when using external reference signal
I perform real experimental tests for optical communications using DCO-OFDM. The transmitted signal is uploaded into an AWG (arbitrary waveform generator), then bias (2.5 V) is added before adopting ...
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Mapping from Antenna ports to Antenna Elements 5G NR
I have a question related to CSI-RS channel estimation.
Let us assume that the base station has 64 antennas and we decide to use 32 antenna ports for CSI-RS transmission. Also, UE has 4 antennas.
My ...
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Pilot-based channel estimation in OFDM systems with fractional delays
Most studies on OFDM-based communication systems consider that multipath channels consists of a limited set of taps in the discrete-time domain. However, this only holds if the tap delay is a multiple ...
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Do you recommend a textbook on channel estimation of narrowband communications?
I would like to learn the channel estimation of narrowband communications (i.e., not OFDM).
Do you recommend a textbook (chapter from a textbook) on this subject?
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Tapped Delay Line channel model in wireless communication
Can someone explain the difference between tdl (Tapped Delay Line) -a , tdl-b and tdl-c and their use cases?
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Pilot Signal Overhead
I have a doubt regarding Pilot signals such as CSI-RS in NR.
Using a large number of CSI-RS affects Datarate significantly?
or it is negligible?
Because I wonder it is meaningful that optimize the ...
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140
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Do the effects of OFDM pilot tones spacing appear in time or in frequency domain?
As known, the pilot tones are transmitted via subcarriers predefined and known in the transmitter and the receiver. The pilot spacing is repeated with a certain rate that depends on how fast the ...
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125
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Generating a 2D delay-Doppler channel matrix
I was wondering if anyone here has any idea on 2D delay-Doppler channel and how to generate the channel matrix?
Even a hint or a resource would be helpful. I just want to understand and visualize the ...
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1k
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Understanding MMSE equalizer equation
I have read many online materials and journal paper where the equation for MMSE equalizer is given as:
$G_{MMSE}$ = $H^H(HH^H+\nu^2I )$
where $H$ is the channel, $H^H$ is its hermitian. $\nu^2$ is ...
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122
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Unstable Phase in Channel Impulse Response
I'm using DW1000 UWB radio transceiver and extract its channel impulse response (CIR). The CIR output by the transceiver is the complex baseband CIR. In a static environment, the CIR is a LTI filter ...
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124
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bit reversed order of FFT matrix for channel estimation
Although the question seems similar to this one HERE, but what I want to ask about is little bit different.
Assume we have a signal $X$ whose length is $N$x$1$, we convert that signal into time ...
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Channel estimation using bit reversed order of FFT matrix
Is it possible to use the bit-reverse order of FFT instead of FFT to estimate the channel?
Based on my reading, I found that bit reversed order of FFT matrix can diagonalize the channel, but ...
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time-domain channel estimation based on two vectors optimization
Let's the input data vector $X = [X_1, X_2, X_3, X_4, X_5,X_6,X_7,X_8];$ where $[X_7,X_8]$ are well known, and the vector $y = h*X$ where $*$ is the convolution operation and $h = [h_1,h_2]$ is the ...
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What is the Co-channel interference in MIMO communication
I try to understand the co-channel interference occurred in MIMO systems with rich multi-path channels, but I couldn't find clear explanation about how it happens and what's its effects to the ...
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Multipath channel estimation in single carrier modulation
I think it’s a basic question, but I couldn’t get it’s clear answer. If we have data symbols $x$ vector of length $N$ x $1$ ; it’s convoluted with a multipath channel $h$ of length $L$ x $1$; the ...
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What can be a limit to the maximum possible power of a pilot signal
In practice, what can be a limit to the maximum power of a pilot signal in wireless communication?
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Unable to estimate for AR model using OLS, Yule Walker and MLE
I am learning estimation methods following the book of Steven Kay, "Fundamentals of Statistical Processing, Volume I: Estimation Theory "
Theory says that if the measurement noise is ...
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Why SRS signalling is used in 5g?
Since DMRS is also being used as a reference signal in PUCCH and PUSCH channel, so why an extra SRS signalling is required.
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Capacity and channel estimation algorithms: explanation of results
I study a spectral efficiency of a system with a precoding scheme with different channel schemes.
Algorithm A for channel estimation gives a smaller estimation error instead of Algorithm B.
I have ...
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Compressive sensing based sparse vector estimation
I am newbie in compressive sensing (CS), I read about compressive sensing and its use for sparse vector estimation. As I understood CS can be used either in time or frequency domain. For me, The part ...
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channel estimation based on time-domain pillots
I am confused if it's possible to estimate the channel based on the time-domain pilots. I mean I have such signal $x$ with length $N$ after taking its $iFFT$ we get $X = ifft(x)$. I have perfect ...
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398
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Should we upsample the channel when upsample the signal
I have an OFDM system with Number of sub-carriers $N= 1024$, modulated data using $QAM$ modulation is transmitted via those subcarriers as follows:
...
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446
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Calculation of channel autocorrelation for LMMSE
I am currently trying to implement an LMMSE estimator/equalizer for a python based ofdm receiver. The actual reception is done with a SDR and iq-samples are stored in a file for the "ofdm-receiver" ...
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LTE Channel Estimation
I am trying understand LTE channel estimation. I have multiple questions:
How much phase shift does a typical LTE channel have?
Can all that be corrected using pilots?
Where do we typically implement ...
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OFDM pilot allocation block type and comb type
As known, the pilot insertion in OFDM can be either bock type or comb type, I think comb type is appropriate for double-selective channel while block type is for frequency selective channel:
In the ...
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Can someone explain or elaborate on the channel estimation and noise variance estimation algorithms used in HF receiver?
For different type of communication, there is different type of algorithms to acquire CSI.
For instance 4G (LTE) network have SRS or DMRS to estimate the channel based on pilots.
I am designing a ...
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A Delay Between Two Filtered Chaotic Signals
it is a common practice to use a shift of cross-correlation peak to evaluate a group time delay of two signals (chaotic signals are included). Can one synchronously and equally filter these chaotic ...
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How determine the delay in my signal practically
I am trying to practically determine filter group delay so that I can try to reduce or adjust for it. I have tried all kinds of methods but still can't get the right result. I know that theoretically ...
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How to reliably compute the group delay of a comb filter
I applied the following FIR comb filter in real-time:
y[n]=x[n]-x[n-40]
Since this is an FIR, the group delay is D=(N-1)/2=20 samples. After applying the filter ...
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System Identification with a Limited Bandwidth Input Signal and Region of Interest
Given a FIR filter $h[n]$. Its action can described as:
$$
\mathbf{y} = \mathbf{H} \mathbf{x} \\
\mathbf{y} = \mathbf{X} \mathbf{h}
$$
where $\mathbf{H}$ and $\mathbf{X}$ is a Toeplitz matrix.
If $h$...
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