Questions tagged [fading-channel]
The fading-channel tag has no usage guidance.
-1
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1answer
14 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-...
1
vote
3answers
45 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
votes
0answers
16 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 :
...
0
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2answers
50 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.
...
0
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0answers
19 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 ...
0
votes
1answer
37 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 ...
0
votes
1answer
34 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 ...
0
votes
1answer
38 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?
0
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2answers
59 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
$$
E\{x\}=P
$$
$$
E\{n\}=0
$$
$$
E\{...
0
votes
0answers
7 views
Need help with understanding the pros and cons of geometric and stochastic based channel models. Which one s preferred under which conditions?
https://www.adv-radio-sci.net/9/165/2011/ars-9-165-2011.pdf
https://ieeexplore.ieee.org/document/7794648
https://pdfs.semanticscholar.org/c301/8463116117ea64f69638e15aa78fe9e84093.pdf
https://www....
0
votes
1answer
60 views
Error detection and correction algorithms for Wireless Body Area Networks
I am working on transmitting ECG signals over wireless body area network based on IEEE 802.15.4 standard. To reduce the BER and increase the signal reconstruction quality, I think that I need to ...
0
votes
1answer
38 views
channel estimation for cdma
I am looking for a method to make a multi-user channel estimation with CDMA.
Here is my question:
Is there a way to estimate multi-user channels with their spreading codes? If yes, what is the ...
-2
votes
2answers
74 views
Digital communication BER performance
I've searched for the theoretical equations of bit error rate over Rayleigh flat fading channel basically for binary phase shift key and 16-Quadrature modulation but i didn't find them, could any one ...
1
vote
1answer
36 views
Questions about reproducing results of a paper on Communication Systems and Wireless Communication
I'm trying to reproduce the results of a paper on Device-to-Device Communication, channel assignment and mode selection (G. Yu, L. Xu, D. Feng, R. Yin, G. Y. Li and Y. Jiang, "Joint Mode Selection and ...
2
votes
0answers
23 views
Is it safe to call this WSSUS channel a Gaussian process?
BACKGROUND:
Equation (3.6) of Wireless Communications by Goldsmith gives the baseband impulse response of a time-varying channel as:
$$
c(\tau,t) = \sum_{n=0}^{N(t)}\alpha_n(t)e^{-j\phi_n(t)}\delta(\...
1
vote
0answers
37 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^{-\...
0
votes
2answers
334 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)$, ...
0
votes
1answer
211 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 ...
0
votes
1answer
32 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 ...
0
votes
1answer
67 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 ...
0
votes
1answer
47 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 ...
0
votes
1answer
43 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 ...
0
votes
1answer
382 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 ...
5
votes
2answers
324 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 ...
0
votes
2answers
274 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"?
0
votes
1answer
74 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 ...
0
votes
1answer
130 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 ...
0
votes
1answer
86 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 ...
0
votes
1answer
451 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, ...
-1
votes
1answer
95 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-...
0
votes
0answers
42 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 ...
0
votes
2answers
111 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 ...
0
votes
2answers
30 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 ...
1
vote
0answers
80 views
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 ...
0
votes
1answer
113 views
why did convolution coding achieve BER less than Reed-Solomon?
I tried convolutional coding and Reed-Solomon (RS) (block coding technique) for wireless channel where the input data is bitstream.
Convolutional coding achieved lower BER comparing with RS. If the ...
2
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0answers
366 views
PortAudio: sound fade in/out by scaling sample data
I've done already some fade in or fade out effect in portaudio, but that is not working properly.
My callback function:
...
2
votes
1answer
52 views
Transmitting over Unknown Fading Channel
I have a system with no diversity and the channel's coefficients change every $T = 10\text{ bits}$ transmitted. The channel estimation system has a flaw and detects the channel's coefficients equal to ...
0
votes
1answer
357 views
What is the suitable mathematical form of the multipath channel impulse response?
I am trying to understand the nature of a wireless multipath channel impulse response but I am a bit confused
while interpreting the time domain multipath impulse response.
There are different ...
1
vote
2answers
702 views
Correct way to simulate Rayleigh fading for indoor environments
I am trying to simulate indoor communications with all components included. But something disturbs me when it comes to Rayleigh fading part.
I am adding my rayleigh fading to the transmitted signal ...
3
votes
0answers
42 views
Actual measurements of the influence of fading and multipath on HF radio communication
I'm looking for papers or books that contain actual measurements of the influence one has to expect in HF radio communication. I'm interested in this, because i've simulated the influence of a ...
0
votes
1answer
399 views
Flat vs frequency selective fading in MC-CDMA?
I am trying to simulate an MC-CDMA system. I have NXK matrix $S$ which consists of subcarriers ($s_n,_k$ represents subcarrier $n$ of user $k$) and KX1 vector $X$ consists of user symbols. So my ...
1
vote
2answers
266 views
Why do we express complex noise as Gaussian distributed while the channel is Rayleigh distributed?
I have a confusion regarding the distribution of noise and channel fading. As we know channel fading is usually modeled with Rayleigh fading since it has Gaussian distributed real and imaginary ...
0
votes
1answer
135 views
MIMO System Model in Matlab
I have this lame doubt which has ended up confusing me which is probably trivial. I am modelling a MU-MIMO system with a Rayleigh fading channel. I have created a wanted signal as an OFDM signal, and ...
1
vote
0answers
85 views
Ideal channel in OFDM simulation
I am trying to simulate an OFDM based system in MATLAB where the estimated channel in the reciever is fed back to transmitter. As a proof of concept I wanted to return the ideal channel. I used the ...
0
votes
1answer
564 views
Rayleigh Fading Simulation
I have a question about simulating Rayleigh Fading channel.
I know theory behind the Rayleigh channel and it is sum of two Gaussian random variable where the amplitude is Rayleigh distributed and the ...
3
votes
1answer
411 views
Educational purpose - What is the correct way to simulate a multipath fading channel which has ISI
I am following the codes for rayleigh fading channel given in the webpage: http://www.raymaps.com/index.php/m-qam-bit-error-rate-in-rayleigh-fading/
I am confused and need help in clarifying some ...
0
votes
1answer
422 views
Zigbee Transceiver Using OQPSK Modulation under Fading Channels
I am working on transmitting ECG signal over wireless body area networks. According to IEEE802.15.4 standards , I am using ZigBee transceiver at 2.4 GHZ . Complex baseband equivalent channel model is ...
0
votes
1answer
97 views
Brief introduction to wireless communication and communication terminologies [closed]
In the Question Design of equalizer for wireless communication the diagram of a basic communication system is presented with informative points and discussions. My Questions are:
Considering the ...
-2
votes
3answers
115 views
Channel modelling for wireless body area network
According to IEEE 802.15.4a
In WBAN, pulses are transmitted from an antenna , diffract around the body and can reflect off of arms and shoulders. so there are always two clusters of multi path ...
4
votes
2answers
601 views
Flat fading criterion of OFDM subcarrier spacing
I have always thought that the OFDM subcarrier spacing $\Delta f$ is chosen such that
not too small because Doppler spread can destroy subcarrier orthogonality
not too large to avoid Cyclic Prefix (...
