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Questions tagged [multipath]

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Free space path loss and Rician fading

Let a be a qam symbols vector , they pass through ofdm modulator by applying ifft and adding cyclic prefix and I apply comm.RicianChannel function for modeling rician fading I want to introduce also ...
ahmed bennani's user avatar
1 vote
1 answer
26 views

Transmit/receive signal of two-path propagation model

In wireless communication, when the transmitted signal is $x$ and the received signal is $y$. Please tell me why the formula below holds true. \begin{align} y(t) &= \left( e^{-\jmath 2\pi f_c\...
Ryo Onishi's user avatar
1 vote
0 answers
51 views

OFDM design considerations for choosing the number of subarriers $N$

I was trying to think of all possible constraints or factors that needs to be taken into consideration while designing an OFDM-based wireless communication system (For example, LTE, 5G technologies ...
wanderer's user avatar
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1 vote
3 answers
79 views

which type of diversity is used by rake receivers?

My question is: Which type of diversity technique is used by the rake receivers? In Bahai, et. al. "Multi-Carrier Digital Communications Theory and Applications of OFDM," Second Edition, ...
Ali's user avatar
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2 votes
1 answer
1k views

How to code Rician fading channel gains from k-factor?

I know that MATLAB provides some built-in functions but I am not interested in those. I want to know how can we code to obtain the Rician fading channel gains from normal or Gaussian distributions. ...
ZZ1's user avatar
  • 23
1 vote
1 answer
56 views

Understanding Pathloss and latency

In my class on wireless communication, I came across the following sentence: The round trip path-loss can be defined to include aspects such as attenuation and/or latency etc Hence I am looking for ...
chaaru's user avatar
  • 37
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1 answer
32 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}...
Jonathan1234's user avatar
1 vote
0 answers
67 views

Super resolution for narrowband signal

How effective it is to apply super resolution techniques (like MUSIC, ESPRIT) on low bandwidth signals for indoor (BW=30Mhz) and outdoor (BW = 1MHz) location estimation?
RAVI SHARMA's user avatar
1 vote
1 answer
216 views

How to determine the number of multipath?

In a multipath propagation environment if we take the time index of reach channel tap by the integer multiples of sampling periods, assume the RMS delay spread $ \sigma_{tau} $ and maximum excess ...
ColinGuolin's user avatar
0 votes
1 answer
227 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 ...
ColinGuolin's user avatar
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80 views

Forming the estimation manifold for a 2-D beamformer

Given an array of L sensors in a uniform planar array, with known positions in space, I would like to estimate both the angles of arrival and delays from a point source under multipath conditions ...
Thefoilist's user avatar
3 votes
0 answers
245 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 ...
Coniferous's user avatar
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0 answers
73 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 ...
nashynash's user avatar
  • 105
3 votes
2 answers
2k views

MUltiple SIgnal Classification (MUSIC) Implementation

I have a linear 4 element antenna array currently in my design, I am able to obtain the I/Q data from each antenna. Now I am trying to implement the MUSIC algorithm to obtain the AoA (Angle of Arrival)...
radar101's user avatar
1 vote
3 answers
122 views

Why does altering path length in radio transmission alter the phase of the received signal?

I do have a very naive yet bothering question: Assume I send a sinusoid signal \begin{equation} A*cos(2\pi ft+ \phi_0) \end{equation} over a radio channel. Assume there is only a LOS-path for each ...
fl0ta'''s user avatar
  • 49
1 vote
1 answer
84 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?
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59 views

MIMO multipath delay [duplicate]

How is multi-path delay dealt with in MIMO systems? Most of the theory I have read on MIMO doesn't address multipath delay and assumes the multipath interference is limited to secondary antenna ...
FourierFlux's user avatar
0 votes
1 answer
101 views

Wireless Channel Multiplicative Model

Let's assume a SISO channel in the equivalent baseband, the standard channel model (discrete) is: \begin{align} y(k) = h(k)x(k) + z(k) \tag1 \end{align} Where $y(k)$ is the detected signal, $h(k)$ ...
ulfgar's user avatar
  • 28
2 votes
1 answer
824 views

How to demodulation BPSK in real case(through a channel)?

I am configuring a channel sounding system. Using PRBS to correlate for time delay. Some details as follow. Generate PRBS. Using BPSK to modulate PRBS and Tx transmit. Rx receive signal and ...
wrxue's user avatar
  • 23
0 votes
1 answer
116 views

Simulating multipath channel

I'm trying to simulate a multipath channel to see how it would affect my signal. So considering my channel is LTI, I can model it as an FIR filter. I've been reading Telecommunication Breakdown and ...
researcher9's user avatar
0 votes
1 answer
4k 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: $\...
shahriar's user avatar
-1 votes
2 answers
100 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 ...
Stat7's user avatar
  • 99
-1 votes
1 answer
531 views

What factors affect the propagation delay at wireless communication?

Generally, the signal propagation delay is d/c. d is a distance between a transmitting antenna and a receiving antenna. c is light speed. However in NS-3, there is Random Propagation Delay Model ...
jack han's user avatar
0 votes
2 answers
224 views

MU-MIMO Sensitivity to Line of Sight (LOS)

Why do researchers talk about MU-MIMO being "less sensitive to line of sight" / "LOS Okay"? For example in this video, time=[00:40,00:42] Similarly, "User separation based on spatial channel ...
Tompa's user avatar
  • 1
3 votes
1 answer
105 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 ...
jabak hamad's user avatar
2 votes
1 answer
266 views

Where in the signal chain is Channel Equalization applied?

I am reading about channel equalization and I am somewhat confused on where in the signal chain channel equalization is normally applied and if it's before or after a correlator detector or matched ...
FourierFlux's user avatar
0 votes
1 answer
80 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 ...
Faizan Zaheer's user avatar
0 votes
2 answers
223 views

Cross-correlation peaks in acoustic multi-path conditions

Consider a speaker and a microphone are placed in a multi-path environment and the audio signal to be transmitted is LFM(chirp) signal, the time of arrival of the audio signal is computed by cross-...
WSL's user avatar
  • 59
1 vote
2 answers
3k 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"?
New_student's user avatar
1 vote
0 answers
66 views

How do state of the art echo cancellation algorithms deal with variable propagation times of sound due to multiple speakers or reverberation?

I understand how echo cancellation works with a single speaker and no reverberation (using adaptive filtering and freezing the coefficients during double-talk). However, in cases with more than one ...
Steve Smith's user avatar
-1 votes
1 answer
186 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-...
New_student's user avatar
1 vote
1 answer
761 views

Is Phase Locked Loop is essential for BPSK signal reception?

I'm noob in DSP studying BPSK communication between speaker and microphone using acoustic signal. I read article of this BPSK communication which says it needs Phase Locked Loop(PLL) sequence to match ...
JayHeo's user avatar
  • 53
1 vote
1 answer
1k 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 ...
tuner's user avatar
  • 635
1 vote
0 answers
92 views

Random multipath power and delay generation

I'm trying to simulate an indoor environment that exhibits multipath propagation. However, I don't know how to generate random multipath variables like path power and path delay (power-delay profile)....
Furkan Küçük's user avatar
1 vote
0 answers
188 views

OFDM in multipath channel simulation in it++

I am trying to simulate OFDM for an multi-path channel. I am using it++ for simulation. ...
Nithin's user avatar
  • 111
2 votes
1 answer
165 views

How to accurately model wideband RF reflections?

I would like to model a transmitter and received pair, both sampling at the same bandwidth (not clock synchronized), where there are a number of reflectors. The time delay due to the reflectors can be ...
awelkie's user avatar
  • 153
0 votes
1 answer
109 views

OFDM Times of Arrival of multipath

Assume i have received a known analog OFDM symbol (such the Short-Training-Field (STF) in WiFi systems), call it $s(t)$ with a known DFT per subcarrier, in the presence of multipath and absence of ...
Ahmad Bazzi's user avatar
1 vote
1 answer
134 views

Multipath fading in wireless channel - parameter needed

I’m trying to implement in Matlab the magnitude of the channel taps of the wireless communication system that is described at page 23 (Section 2.1.4) in the classic book of D. Tse, Fundamentals of ...
Yannis Avguleas's user avatar
0 votes
2 answers
157 views

I want to know if there is a practical way to find out if multipath propagation is significant for audio in a given environment?

I am employing audio signals generated by a mechanical press for Blind Signal Separation. But, prior to algorithm application, I need to clarify if the signal strengths coming in multipath (except ...
Indi's user avatar
  • 21
2 votes
2 answers
484 views

Multipath resistance of spread spectrum systems

I have been reading about various telecommunications technologies and one thing keeps being repeated many times without a clear explanation - that spread spectrum is not only resistant to multipath ...
JohnEye's user avatar
  • 121
3 votes
0 answers
196 views

Problem using MMSE estimation of channel frequency response

I need to model the minimum mean square error (MMSE) performance in estimating channel frequency response. I have channel's power delay profile (PDP) as a table with tap delays and powers. The ...
Zvord's user avatar
  • 41
2 votes
1 answer
148 views

Sound reflections plot

I have sound files that contain recordings of an impulse signal in a room. I'd like to make such a plot from it. I basically want to compare early reflections. How do I go about it? Is just taking ...
damcko's user avatar
  • 23
2 votes
4 answers
352 views

Channel impulse reponse multipaths

I find this image : Does it mean that at 0ns there is one path, 10ns second path, ... and approximately at 130 ns, there is a power path?
Zaertiu's user avatar
  • 131
0 votes
0 answers
575 views

Effect of pathloss on signal power

Consider I have two transmitters $tx_1$ and $tx_2$ at say a distance of $d_1=5\text{ m}$ and $d_2 = 15\text{ m}$ respectively from a receiver. Now, if I consider the effect of path loss in such a ...
smyslov's user avatar
  • 349
2 votes
1 answer
375 views

Gaussian, Rayleigh, and Exponential RVs

I am doing some simulations on the performance of OFDM systems in multi-path channels and I am confused about something. It is explained below: Assume that we have a multi-path channel with a number ...
Noor's user avatar
  • 337
0 votes
1 answer
71 views

Modeling multipath distortion and shifting by fractions of a sample

I am working on modelling some FM transmitted signals, and I'm trying to figure out how to model the effects of multipath channels. The most obvious method is to delay the signal by some integral ...
RJTK's user avatar
  • 101
1 vote
1 answer
283 views

OFDM intra-block multipath interference

We know that OFDM eliminates the inter-block intereference. But there are still multipath interference in a single OFDM block(symbol). How does LTE handle this intra-block interference induced by ...
Robert Fan's user avatar
0 votes
0 answers
171 views

multipath propagation

i recorded a tone between two devices and applied cross correlation on the recorded and the sent signals. I want to know if there is a multipath effect on my result (on MATLAB). what can i use for ...
hanaa's user avatar
  • 101
2 votes
1 answer
209 views

Transmit diversity vs multi-path?

Are transmit diversity signal and the multi-path signal same? Multi-path contains LOS+delayed and attenuated/distorted versions of it and transmit diversity signal contains LOS1+delayed LOS2+ +delayed ...
GJK's user avatar
  • 83
9 votes
1 answer
1k views

Ultrasonic signal detection

I have created a fairly simple TDOA system that uses ultrasonic signals emitted from two speakers to geolocate (relative to the speakers) mobile phones. The two signals are separated by frequency. ...
Jim Clay's user avatar
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