Questions tagged [fading-channel]
The fading-channel tag has no usage guidance.
109
questions
1
vote
1answer
37 views
On-Off keying for wireless communication channel estimation
Let us assume I have $k$ (a fixed number) sensors in a wireless sensor network with unknown channel statistics $\{h_1,h_2 \ldots, h_k\}$.
In my system model, each of these $k$ sensors has an ...
0
votes
0answers
45 views
Coherent detection in fading channel
I want to design an optimum receiver for a fading AWGN channel for ML Detection. I know that in the case of non-coherent communication we have to use an energy detector(even when the fading channel is ...
0
votes
1answer
25 views
Log Path Loss Model with Directivity Accounted
Suppose that I have the log Path Loss distance model described here https://en.wikipedia.org/wiki/Log-distance_path_loss_model
$$PL(d,\gamma) = P_{t}-P_{r}=PL_{0}+10\gamma log_{10}\frac{d}{d_{0}}+X_{g}...
0
votes
1answer
38 views
Relation between SNR and fading channel coefficients?
I am trying to understand the following thing:
Does the average signal to noise ratio (SNR) depends on fading channel coefficients ?
Any help in this regard will be highly appreciated.
0
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0answers
30 views
Related to successive interference cancellation?
I am trying to understand the following query: " Is it necessary to do channel estimation to perform successive interference cancellation at the receiver operating over fading channel"
Any ...
-1
votes
1answer
428 views
What are TDL and CDL channel models in principle, and which variation can be used for indoor and outdoor environment, respectively?
I am making a simulation using 5G-toolbox in Matlab. IN 5Gtoolbox we have two kind of channels, CDLChannel and TDLChannel. Now, CDL means Clusteresd Delay Line, and TDL means Tapped Delay Lines. But ...
0
votes
0answers
45 views
Frame synchronization for single carrier burst applications in fading channels
I recently started to implement communication systems with software-defined radios in GNU Radio. In my system design, I am planning to transmit data in burst mode, the frames will be not sequentially ...
0
votes
1answer
50 views
Log-normal shadowing and mean power
Let's assume I'm receiving a signal with power measured in dBm shadowed according to the normal distribution, i.e. $P_{\text{dBm}} \sim N(0,1) $.
If there is also a normally distributed noise power $...
1
vote
2answers
97 views
Rayleigh Fading
I am calculating the capacity of $K$ channels between a transmitter and $N$ receivers in a cellular scenario. I use the following equation:
$$C_n^k = B\log_2\left(1 + \frac{Ph_n^k}{N_0B + I_n^k}\right)...
1
vote
1answer
40 views
Related to channel power gain
I am having a doubt that why channel power gain is denoted by $|h|^2$. For example, if the signal received is
$$y(n) = hx(n)+w(n)$$
where $x(n)$ is transmitted signal with power $P$ , $w(n)$ is AWGN ...
-1
votes
2answers
47 views
How is the distribution of the received signal affected if the transmitted signal is changed from complex Gaussian to PSK
Suppose the received signal is $y(n) = h_0s(n)+w(n)$----(1)
Where $h_0, s(n), w(n)$ all are distributed as zero mean complex Gaussian. Thus I know that $y(n)$ will also have the same distribution.
If $...
0
votes
1answer
26 views
understanding the distribution of received signal
In one of the research paper following equations are given :
$y(n) = h_0s(n)+w(n),d = 0$
$y(n) = h_1s(n)+w(n),d = 1$
where $n$ ranges from $1$ to $N$ and
$h_0,h_1$ are wireless channel assumed as $\...
0
votes
0answers
38 views
Related to wireless channel fading
I am reading some papers wherein a wireless channel is assumed as zero mean circularly symmetric complex Gaussian (ZMCSCG) with unit variance and it is also mentioned that the channel undergoes ...
0
votes
1answer
47 views
related to random nature of wireless channel
I am reading An Approximate BER Analysis for Ambient Backscatter Communication Systems With Tag Selection wherein it is mentioned that "when the distance between two nodes is very small and line ...
0
votes
1answer
71 views
What is the meaning of the channel gain is normalized
Transmitting the signal $x$ over the channel $h$ and affected by noise $n$ can be expressed:
$y = hx + n$
$h$ is the channel gain, that is known for me. I sometimes see phrases saying "when the ...
0
votes
1answer
74 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 ...
0
votes
0answers
22 views
FWGN model and MATLAB implementation
I am studying channel modeling, at the moment, in the book: "MIMO-OFDM wireless communications with MATLAB", the explanation about the model is as follow:
The code for generation of Doppler ...
0
votes
1answer
48 views
How is channel frequency response/channel state information related to free space path loss?
As we know, the path loss can be described by the equation as
$$
\frac{P_{r}}{P_{t}}=D_{t} D_{r}\left(\frac{\lambda}{4 \pi d}\right)^{2}
$$
In the OFDM system, such as Wi-Fi, there are infinite paths ...
2
votes
0answers
49 views
About discrete time model for wireless channel
I am trying to understand Section 2.2.3 of the book "Fundamentals of wireless communication" by Tse and Viswanath. In this section the authors explain how to go from the continuous time ...
0
votes
0answers
35 views
Received signal's power under Raleigh fading
I am trying to understand how to calculate the power of a received signal under Raleigh fading.
What I gather is that the Rayleigh fading is a complex Gaussian random variable and that the multipath ...
0
votes
0answers
96 views
Zero padding OFDM equalization
In ZP-OFDM, The convolution is linear. it's different from CP-OFDM which is circular convolution leading to have one tap equalizer in frequency domain.
if I have a ZP-OFDM system, and we have a signal ...
0
votes
1answer
181 views
Fast/Slow Fading: How are doppler shift and coherence time related?
In the literature I've read that fast fading happens if the bit duration is larger than the coherence time of the channel.
The coherence time of a channel is proportional to $\frac{1}{f_{Doppler}}$. ...
0
votes
1answer
53 views
Non Coherent BPSK with no Channel State Information at the receiver
Where or what is the proof for the failure of BPSK in fading channel when we have no knowledge of the fading coefficient $h$ at the receiver in the equation $y=hx+w$, where $x$ is BPSK symbol equally ...
1
vote
0answers
77 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 ...
0
votes
1answer
33 views
Correlated fading channel: transmit and receive antenna correlation matrices
I am trying to create a non-i.i.d channel: correlated Rayleigh fading channel.
$$ H= R_H \cdot H_o,$$
where $H_o$ is i.i.d. channel ( uncorrelated) and $ R_H$ is a channel correlation matrix, is ...
1
vote
0answers
153 views
Degrees of freedom in coding (for a communication channel)
I was reading on my lecture slides about how to achieve diversity (i.e. transmit more copies of the same message in order to avoid its corruption; this technique may be realized by repeating the ...
0
votes
1answer
37 views
Rayleigh fading channel as a scalar quantity [closed]
In most cases rayleigh channel is a vector. can a rayleigh channel be a scalar quantity i.e., can we have only one element in rayleigh fading channel.
1
vote
1answer
40 views
Is time varying channels same as circulary symmetric complex gaussian?
From the literature i understood that if the channel is non time varying then we can consider it as circularly symmetric complex gaussian distributed. So can we consider the same if the channel is ...
1
vote
1answer
37 views
Hf ionospheric channel model for large bandwidth
I know some models like the Watterson model for HF ionospheric channels but those are limited to narrow band frequencies.
Are there some models to bandwidth like 12kHz up to 24 kHz?
1
vote
0answers
48 views
Detect orthogonal sequence with fading
For a set of $N$ orthogonal sequences $\textbf{A}^i = \{a_1^i,a_2^i,...,a_M^i\}, i =1 ..N$, the detection of these sequences can be done by calculating the inner product (dot product) of receive ...
1
vote
0answers
90 views
Is MMSE equalizer necessary?
For observation $y$, channel coefficient $h$ and gaussian noise $w \sim \mathcal{CN}(0,\sigma^2)$,
$$y = hx + w \tag{1}$$
Note that for OFDM system, (1) is assumed channel input-ouput equation on ...
0
votes
2answers
134 views
Meaning: channel unknown and known at the transmiiter
What does "channel unknown" and "known at the transmitter" mean?
In books about signal processing, it has always mentioned it if capacity or transmission (estimation) is discussed. I can't understand ...
1
vote
0answers
44 views
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 ...
0
votes
0answers
23 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,...
0
votes
1answer
25 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 ...
1
vote
2answers
102 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 ...
0
votes
0answers
79 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)...
0
votes
1answer
2k 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:
$\...
0
votes
2answers
57 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 ...
0
votes
1answer
43 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 ...
0
votes
1answer
245 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 ...
-1
votes
1answer
56 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-...
3
votes
3answers
449 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
2answers
673 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
25 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
861 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
87 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
49 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
votes
2answers
782 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\{...
1
vote
1answer
98 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 ...
