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### How to add Rayleigh Fading Coefficient to a BPSK signal with AWGN?

I have a problem with my code. I saw many programs that add the coefficients of rayleigh like this: h=1/sqrt(2)*(randn(1,N)+1i*randn(1,N)), where N=number of bits. ...
64 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 ...
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### 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 ...
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### 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 ...
12 views

### Simulating Rayleigh channel - Problem with adding channel coefficents

I am currently trying to simulate a Rayleigh channel using python (numpy). Full Jupyter Notebook on GitHub: Jupyter Notebook I assume that the channel changes with each new symbol. So I create myself ...
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### 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 ...
30 views

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 ...
71 views

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 ...
102 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 $\frac{1}{f_{Doppler}}$. ...
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### 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 ...
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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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### SNR in case of complex channel and fading

I am trying to estimate SNR mathematically given in a paper. $$y = hx + n$$ $h$ is channel fading, that is Rayleigh in my case, while $n$. Both $h$ and $n$ are random variables. ...
30 views

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 ...
93 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 ...
29 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.
39 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 ...
36 views

### Gain and average gain of two-path channel

For two-path channel with no loss or phase shift in the reflection, Why the gain of the channel at radio frequency less than average gain of the channel?
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### 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?
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### 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 ...
71 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 ...
81 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 ...
38 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 ...
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### 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 ...
38 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 ...
165 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 ...
49 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-...
303 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 ...
552 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. ...
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 ...
630 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 ...
78 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 ...
47 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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