Questions tagged [fading-channel]

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Time variant frecuency selective fading in matlab

I am traying to simulate a frequency selective fading channel in Matlab and I have faced with some issue/questions during the implementation. It is a DSSS (BPSK) modulation and the code is organized ...
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14 views

How to estimate the channel in DS CDMA system

I am working with DS-CDMA system based on multi-path Rayleigh channel,My question, how can I estimate the channel from the received signal to cancel the effect of channel? for example in OFDM system ...
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30 views

How to generate rayleigh fading coefficients in matlab

I want to calculate received SNR for each cellular user CUs, so i want the corresponding transmission power P of base station BS to each user, the noise, and the channel gain coefficient of the ...
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9 views

I don't know why the packet size is considered in this packet reception probability equation

https://www3.nd.edu/~mhaenggi/pubs/broadnets04.pdf In 3 page of this paper, the packet reception probability without interference is $e^{-\theta N Ad^2/ P}$. $\theta$ is sinr threshold. $N$ is a ...
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Why are the following two packet reception probabilities different?

https://www3.nd.edu/~mhaenggi/pubs/broadnets04.pdf In 3 page of this paper, the packet reception probability without interference is $e^{-\theta N Ad^2/ P}$. $\theta$ is sinr threshold. $N$ is a ...
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12 views

Smooth Cross-Fading [duplicate]

I want to cross-fade from one signal smoothly to another signal. Example: Signal1 = 5 Signal2 = 1 I already looked for algorithms/ procedures but could not find anything helpful. As I am not that ...
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22 views

why if I want to create a rayleigh fading channel with $E[|H_{i,j}|^2]$,I should multiply $\sqrt{\frac{1}{N_R \times N_T}}$?

I want to create a rayleigh fading channel,and my classmate told me that I can create an $N_R \times N_T $ channel $\mathbf H$ with $E[|H_{i,j}|^2]$,that is,$\sqrt{\frac{1}{N_R \times N_T}}\times CN(0,...
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1answer
18 views

Small Scale Fading time varying or position varying

I would like to ask how small scale fading can affect a transmission with time. The particular system is an antenna transmitting an ASK modulated signal at 915MHz and with bandwidth between 200KHz to ...
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1answer
34 views

Notes or books to quickly get started on the basics of signal processing or wireless communication

I'll soon start working in signal processing, specially wireless communication systems. Hence I'd like to get a quick understanding of MIMO and related systems, for example, the topics like: 1) where ...
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42 views

Two different models of Rician fading

The amplitude of the signal in Rician fading case is characterized by the Rician distribution (let's call this model 1). However, the received power in Rician fading is sometimes modelled as (model 2)...
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1answer
196 views

channel gain calculation

I want to calculate the SINR term in an up-link of wireless communication system but there is different models for simulation. I want to know what is the exact meaning of |h|^2 in this formula: SINR = ...
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1answer
28 views

Detecting multi-path propagation when one acoustic signal is dominant

I am sending an acoustic signal from a source to a receiver where there are limited number of paths the signal can travel. I want to detect if there has been multipath propagation or not when one path ...
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1answer
33 views

Assessing relative wireless channel quality using Capacity and Condition Number CDFs

I have Channel capacity analysis figures for two wireless channels show below: My question: While ergodic capacity in the first subplots are very clear in conveying the channel capacity, How to make ...
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83 views

SNR and Correlation

Signal to Noise ratio is essentially the ratio of the signal power to the average noise power. Correlation is the similarity of two signals. Assuming a signal travels through a channel or medium, and ...
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22 views

Channel information from power spectra

Linked below is a previous post regarding a multipath channel. Equalisation of FFT spectra I am reusing the images here: The first image is that of the power spectra when there is no multipath and ...
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1answer
64 views

Validating Jakes model in Rayleigh Fading channels

I am trying to validate the Jakes model by comparing the autocorrelation function given by $ \rho(\Delta t ) = J_{0}(2 \pi f_{d} \Delta t)$, where $ f_{d} $ is the maximum Doppler shift, $ J_{0} $ is ...
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32 views

Automotive Radar Simulation

I am looking to simulate a radar channel and a waveform to test some ideas from other signal processing domains on automotive radar. However, I have no experience with the typical automotive radar ...
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1answer
30 views

What's the effect of spread spectrum on frequency- selective channel

In brief, we consider the channel as frequency-selective channel if the frequency of the signal is larger than then frequency of channel. So, does using the spreading spectrum change the frequency-...
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84 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 ...
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52 views

Frequency selective channel modeling using rayleighchan object in matlab

I intend to model a frequency selective channel using matlab "comm.RayleighChannel" object. Consider the following command, which sets the parameters of Rayleigh channel : ...
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2answers
281 views

BER of QPSK modulation in Rayleigh fading channel model

i am having trouble deriving a BER analytical expression for QPSK modulation system operating in a Rayleigh Fading channel model. Could anyone direct me to a reference that would help in this matter. ...
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23 views

Channel models for wireless body area networks

To transmit a signal over wireless body area network, the signal is transmitted over a fading channel with additive white Gaussian noise. The channel model can be obtained from the IEEE standards. My ...
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1answer
218 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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1answer
50 views

Channel estimation

In single-carrier systems, at the receiver, when we need to do channel estimation and equalization? Do we need to do before timing synchronization and CFO correction or before it? And, please let me ...
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1answer
45 views

Designing Rayleigh Fading Wireless Channel with particular properties [closed]

I have some information on particular wireless channel between an Access Point(AP) and K users as described in the picture below: How i can create this channel in Matlab?
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2answers
157 views

How to find the instantanous SNR over Fading channel

I would like to prove that the instantnous SNR of flat fading channel $$y=hx+n$$ is $$\gamma=\frac{|h|^2}{N_0}P$$ where $E\{z\}$ is the expectation of $z$ and $$ E\{x\}=P $$ $$ E\{n\}=0 $$ $$ E\{...
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1answer
67 views

Error detection and correction algorithms for Wireless Body Area Networks

I am working on transmitting ECG signals over wireless body area network based on IEEE 802.15.4 standard. To reduce the BER and increase the signal reconstruction quality, I think that I need to ...
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1answer
67 views

channel estimation for cdma

I am looking for a method to make a multi-user channel estimation with CDMA. Here is my question: Is there a way to estimate multi-user channels with their spreading codes? If yes, what is the ...
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2answers
99 views

Digital communication BER performance

I've searched for the theoretical equations of bit error rate over Rayleigh flat fading channel basically for binary phase shift key and 16-Quadrature modulation but i didn't find them, could any one ...
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1answer
41 views

Questions about reproducing results of a paper on Communication Systems and Wireless Communication

I'm trying to reproduce the results of a paper on Device-to-Device Communication, channel assignment and mode selection (G. Yu, L. Xu, D. Feng, R. Yin, G. Y. Li and Y. Jiang, "Joint Mode Selection and ...
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27 views

Is it safe to call this WSSUS channel a Gaussian process?

BACKGROUND: Equation (3.6) of Wireless Communications by Goldsmith gives the baseband impulse response of a time-varying channel as: $$ c(\tau,t) = \sum_{n=0}^{N(t)}\alpha_n(t)e^{-j\phi_n(t)}\delta(\...
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39 views

CDF of product of two *translated* exponential variables

It is known that the CDF of the product of two exponential random variables is given by this answer If $X$ and $Y$ have rate parameters $\mu$ and $\lambda$, so their pdf's are $f_X(x) = \mu e^{-\...
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2answers
773 views

How to compute the channel gain from the path loss model of a wireless channel

I did my research but I did not get a satisfying answer. We have a transmitter and a receiver over a wireless communication channel. The channel's path loss is modeled as $ 128 + 37 \log_{10} (d)$, ...
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1answer
438 views

How can I generate time-variant Rayleigh channel in MATLAB

One of known models for channel simulation is called Rayleigh Fading channel, it's usually used to simulate wireless channel in time variant/invariant. As I know, Rayleigh fading channel can be ...
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1answer
41 views

Need information about following channel model

The following research paper is for blind channel equalization and the author has modeled the channel as 7 tap weights https://ieeexplore.ieee.org/document/1096877 On page 3 it has shown the ...
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1answer
86 views

What's the difference between SISO and SIMO in using matched Filters

Suppose we are transmitting a signal $x$ in $OFDM$ with $N$ subcarriers, After performing Parallel/Serial conversion and then N-points FFT, we suppose to have signal $s = IFFT^Hx$, Then adding the ...
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1answer
65 views

When to use Rician fading vs Gain for Directional Antenna

This is a pretty simple question. [The answer might not be simple :( ] If I am using a directional antenna, can I used Antenna gain $G_T=1$ as I am considering Rician Fading between transmitter and ...
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1answer
59 views

Is the Channel shortening similar to Time domain Equalizer (TEQ)

I used to read about Time domain equalizer (TEQ) in many lectures, i.e here , But in many other papers, that's called Channel shortening i.e here . However, in the a two above links, the cost ...
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1answer
690 views

Rayleigh fading with frequency selective fading channel

I Read in one reference that, the Rayleigh distribution is commonly used to describe the statistical time varying nature of the received envelope of a flat fading signal, or the envelope of an ...
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484 views

Intersymbol interference due to limited channel bandwidth

What is the difference between limited-bandwidth induced intersymbol interference (ISI) and ISI due to multipath propagation. I noticed that the delay spread in indoor environment is in the range of ...
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2answers
605 views

what does mean quasi-static channel [closed]

When I read papers about channels, I usually see something Quasi-static Channel, Does "Quasi-static Channel" mean "time-variant channel" or "time-invariant channel"?
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1answer
97 views

Equalizers with low data rate systems

In case of using equalizers with ZigBee systems, what type of fading does the channel show, flat or frequency selective, fast or slow? Is the inter-symbol interference (ISI) problem encountered in ...
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1answer
188 views

How to get a Rician fading channel matrix from a Rayleigh fading channel matrix?

I have a Rayleigh fading channel matrix H. Let's say the dimension is 2000*128. Is there any way to convert this matrix into a Rician fading channel matrix for example κ = 5, 10, 15, etc.? Is there a ...
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1answer
111 views

Performance evaluation in terms of channel MSE and BER

The first figure on the left (in this paper) provides the channel NMSE performance and the the second figure from left provides detector's BER performance. I am curious, when the channel MSE ...
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1answer
630 views

Cyclic prefix length in baseband OFDM with ZF equalizer

My question is about baseband OFDM. I try to plot the BER according to the SNR. I noticed that changing cyclic prefix length does not affect the performances. I.e., following the code below, ...
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1answer
113 views

Explanation of fractional sampling in OFDM [closed]

What is the concept fractional sampling? Is there a relationship between the fractional sampling and interpolation? And how does the fractional sampling help in convert the SIMO (Signal input multi-...
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46 views

Basis Expansion Channel Model

I usually encounter that kind of channel model which is Basis Expansion Channel Model, But I couldn't understand its meaning exactly, and what is it. Could you please help me by providing a simple ...
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2answers
132 views

Demodulation in Rayleigh Flat Fading Channels

A core part of demodulation in Flat-Fading channels is (assuming) the channel as a(random) constant complex number multiplied with your signal. This is done in order to de-rotate the symbol for ...
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2answers
33 views

Which channel coding technique is suitable for wireless SPIHT compressed image: Reed-Solomon or convolutional code?

I want to transmit a SPIHT-based (Set Partitioning In Hierarchical Trees) image compressed image over a wireless fading channel, which will be suitable as channel coding technique: Reed-Solomon or ...
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How to model fading channels in MATLAB?

I am asked to write a MATLAB program for the simulation of the end-to-end transmission of a JPG file through a fading channel by using OFDM technique for one of my courses' term project. I wrote my ...