Questions tagged [multipath]
The multipath tag has no usage guidance.
60
questions
1
vote
0
answers
42
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 ...
- 151
0
votes
0
answers
99
views
Tapped Delay Line(TDL) model in 5GNR
In 38.901, there are five channel profiles for TDL models.
Can someone explain the difference among TDL-A , TDL-B and TDL-C for NLOS and which scenario to use them?
Can someone explain the ...
1
vote
3
answers
64
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, ...
- 95
2
votes
1
answer
651
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. ...
- 23
1
vote
1
answer
48
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 ...
- 37
0
votes
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
$$PL(d,\gamma) = P_{t}-P_{r}=PL_{0}+10\gamma log_{10}\frac{d}{d_{0}}+X_{g}...
- 103
1
vote
0
answers
66
views
Super resolution for narrowband signal
How effective it is to apply super resolution techniques (like MUSIC, ESPRIT) on low bandwidth signals for indoor (BW=30Mhz) and outdoor (BW = 1MHz) location estimation?
- 11
1
vote
1
answer
193
views
How to determine the number of multipath?
In a multipath propagation environment if we take the time index of reach channel tap by the integer multiples of sampling periods, assume the RMS delay spread $ \sigma_{tau} $ and maximum excess ...
- 19
0
votes
1
answer
176
views
How is channel frequency response/channel state information related to free space path loss?
As we know, the path loss can be described by the equation as
$$
\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 ...
- 19
0
votes
0
answers
68
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 ...
- 143
3
votes
0
answers
219
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 ...
- 131
0
votes
0
answers
69
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 ...
- 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)...
- 43
1
vote
3
answers
104
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 ...
- 49
1
vote
1
answer
73
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?
user47976
0
votes
0
answers
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 ...
- 818
0
votes
1
answer
90
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, $h(k)$ ...
- 28
2
votes
1
answer
700
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 ...
- 23
0
votes
1
answer
109
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 ...
- 223
0
votes
1
answer
3k
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:
$\...
- 1
-1
votes
2
answers
92
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 ...
- 99
-1
votes
1
answer
499
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
...
- 9
0
votes
2
answers
213
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 ...
- 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 ...
- 31
2
votes
1
answer
243
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 ...
- 818
0
votes
1
answer
78
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
2
answers
218
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-...
- 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"?
- 639
1
vote
0
answers
65
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 ...
- 11
-1
votes
1
answer
179
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-...
- 639
1
vote
1
answer
703
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 ...
- 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 ...
- 625
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)....
- 195
1
vote
0
answers
177
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.
...
- 111
2
votes
1
answer
160
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 ...
- 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 ...
- 730
1
vote
1
answer
132
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 ...
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 ...
- 21
2
votes
2
answers
477
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 ...
- 121
3
votes
0
answers
191
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 ...
- 41
2
votes
1
answer
147
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 ...
- 23
2
votes
4
answers
338
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?
- 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 ...
- 349
2
votes
1
answer
366
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 ...
- 337
0
votes
1
answer
70
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 ...
- 101
1
vote
1
answer
275
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 ...
- 215
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 ...
- 101
2
votes
1
answer
203
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 ...
- 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.
...
- 12k
0
votes
1
answer
850
views
Simulate a simple multipath channel for OFDM Modulation test. MATLAB [closed]
Hi I need to simulate a simple multipath channel in matlab through which I can send my OFDM transmission signal, I want to test my OFDM receiver design.
So far I have:
...
- 3