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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 ...
Sajjad's user avatar
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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{...
Hiếu Hoàng's user avatar
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1 answer
59 views

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 ...
Rayzain's user avatar
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0 answers
122 views

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 ...
Aragorn's user avatar
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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 ...
zc L's user avatar
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0 answers
59 views

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 ...
unique's user avatar
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1 vote
1 answer
70 views

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 ...
Sonny Wandel's user avatar
1 vote
1 answer
140 views

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 ...
maphado fan's user avatar
1 vote
1 answer
160 views

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. ...
Ryo Onishi's user avatar
0 votes
1 answer
84 views

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 ...
Dan Boschen's user avatar
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1 answer
185 views

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 ...
Obsidian's user avatar
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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 ...
Mahtab's user avatar
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2 answers
117 views

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 ...
Zeynep's user avatar
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9 votes
4 answers
693 views

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 ...
Dan Boschen's user avatar
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1 answer
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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{\...
Math_Novice's user avatar
3 votes
0 answers
67 views

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 ...
Sajjad's user avatar
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2 answers
218 views

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 ...
SAM's user avatar
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0 answers
39 views

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 ...
Sajjad's user avatar
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1 vote
0 answers
187 views

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 ...
gkami's user avatar
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0 votes
1 answer
247 views

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 ...
Lucas Oliveira's user avatar
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1 answer
85 views

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?
Noor's user avatar
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0 answers
129 views

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?
Abhiram Anilkumar's user avatar
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0 answers
63 views

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 ...
Kitae Kim's user avatar
0 votes
1 answer
130 views

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 ...
Fatima_Ali's user avatar
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0 answers
112 views

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 ...
Amit Sravan's user avatar
0 votes
1 answer
1k views

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 ...
SAM's user avatar
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0 votes
0 answers
115 views

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 ...
jleng's user avatar
  • 1
0 votes
1 answer
115 views

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 ...
New_student's user avatar
1 vote
1 answer
86 views

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 ...
New_student's user avatar
0 votes
1 answer
78 views

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 ...
Fatima_Ali's user avatar
-1 votes
1 answer
198 views

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 ...
New_student's user avatar
0 votes
1 answer
94 views

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 ...
Fatima_Ali's user avatar
0 votes
1 answer
61 views

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?
Am Ki's user avatar
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0 answers
60 views

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 ...
Sm1's user avatar
  • 291
1 vote
1 answer
162 views

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.
Nits r's user avatar
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1 vote
1 answer
93 views

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 ...
Noel Miller's user avatar
1 vote
0 answers
87 views

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 ...
Fatima_Ali's user avatar
0 votes
1 answer
93 views

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 ...
Fatima_Ali's user avatar
0 votes
1 answer
377 views

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: ...
Fatima_Ali's user avatar
0 votes
0 answers
419 views

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" ...
Luuke L's user avatar
  • 47
1 vote
1 answer
261 views

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 ...
Sampath's user avatar
  • 15
0 votes
1 answer
663 views

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 ...
Fatima_Ali's user avatar
0 votes
0 answers
56 views

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 ...
Abby_DSP's user avatar
  • 315
1 vote
1 answer
195 views

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 ...
Sergey's user avatar
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3 votes
1 answer
2k views

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 ...
Chika's user avatar
  • 93
0 votes
3 answers
768 views

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 ...
Chika's user avatar
  • 93
4 votes
2 answers
357 views

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 $h$...
divB's user avatar
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