Questions tagged [fading-channel]

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346 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 ...
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1answer
155 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 ...
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0answers
91 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 ...
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1answer
622 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 ...
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1answer
452 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 ...
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1answer
463 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 ...
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1answer
111 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 ...
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3answers
130 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 ...
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2answers
693 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 (...
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0answers
68 views

Help me out in finding the problem in my given MATLAB code of Rectangular Contour Algorithm(RCA)

I am implementing the Rectangular Contour Algorithm (RCA) used for blind channel equalization on 32 Rectangular QAM Signal, polluted with noise and channel effects. It is described in: Khan Q. - ...
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1answer
733 views

Question about path loss exponent estimation from measurment

I have a simple question that confuses me. Assume that we have the following results of a measurement campaign, distance (km) and the corresponding path loss $L_{e}$ (dB). I want to estimate the ...
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1answer
136 views

Capacity loss of fast fading regarding AWGN

The theoric capacity of fast fading channel is: $$ C_{\rm fading}=E\left\{\log\left(1+\lvert h \rvert^2\textrm{SNR}\right)\right\}, \quad\text{with $E$ is expectance operator.}$$ At high SNR: $$\...
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1answer
635 views

How to simulate fading channels in MATLAB? [duplicate]

In this page, an example simulating Rician and Rayleigh fading in parallel is given. I knew that Rician fading simulates both line of sight and none light of sight components, so why do we need to ...
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1answer
345 views

i.i.d Raleigh distributed T tap frequency selective channel

A Single-tap 'flat Raleigh fading channel' is implemented as. ...
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1answer
122 views

Help in analytical expression of BER for M-QAM [duplicate]

I am new in learning deriving BER expression. I am familiar for the case of BPSK in AWGN but cannot understand how the BER expression in Eq(12) in this paper, An Enhanced Spectral Efficiency Chaos-...
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1answer
216 views

Conceptual Question on equalization technique in rayleigh fading channel based on a paper

Question Link http://www.raymaps.com/index.php/theoretical-ber-of-m-qam-in-rayleigh-fading/ gives theoretical expressions for BER in Rayleigh fading channel. Can I use the expression for 64-QAM in ...
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1answer
102 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 ...
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1answer
236 views

FWGN model implementation vs explaination (textbook pages attached)

I came across the FWGN model for multipath channel simulation in the book: "MIMO-OFDM Wireless Comuunications with MATLAB" Here is an explanation about Clarke/Gans model: Some code to generate a ...
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1answer
1k views

AWGN and Rayleigh fading in slow flat fading channels in MATLAB

I wanted to add Additive White Gaussian Noise (AWGN) and involve effect of slow flat fading on my transmitted signal in Matlab. I created noise with zero mean and variance of one by ...
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2answers
8k views

Matlab: Correct method of generating Rayleigh fading channel

A Rayleigh flat fading channel has 1 tap and so there will be no intersymbol interference. if N= 1000; Then, h=(1/sqrt(2))*(randn(N,1)+1i*randn(N,1)); will ...
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1answer
564 views

Matlab: Help in applying equalizer and proper calculation of symbol error rate for QAM modulation in Rayleigh channel

I am unable to understand why the Constant Modulus ALgorithm is not functioning properly for QAM modulation in Rayleigh multipath fading. The same code worked for BPSK in AWGN (previous Question ...
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1answer
179 views

Practicality of the assumption of i.i.d. for Rayleigh channels

I would like to understand how far the assumption of having i.i.d. is accurate/valid (from the practical point of view) when an OFDM system is working in Rayleigh channels. Is this means the channel ...
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1answer
1k views

Matlab: Difference between flat fading and Rayleigh multipath fading, terminologies and concept

The information that I put down are from the site http://www.gaussianwaves.com/2011/05/ebn0-vs-ber-for-bpsk-over-rayleigh-channel-and-awgn-channel-2/ . My QUestions are due to some misconception and ...
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3answers
206 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?
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0answers
59 views

Parameter selection for log distance path loss model

I am currently referring to the following book MIMO-OFDM Wireless Communications with Matlab in which the log distance path loss model is given by the equation: $P_{LD}(d)[dB] = PL_F(d_0) + 10nlog(d/...
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0answers
23 views

Receiver multiple taps

I would like to implement a Rayleigh fading channel for an ASK Modulation. My question is concerning the receiver. How to properly add every tap at the receiver to keep the same length from the ...
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1answer
194 views

Channel capacity with additive Gaussian noise with changing variance

As we all know the capacity for a AWGN channel with constant noise variance is just given by $$\frac{1}{2}\log(1+SNR)$$ What if the variance of the noise changes with the type (assuming the variance ...
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1answer
621 views

Amplitude distribution of Rician faded complex signal

I have question regarding Rician fading simulation. I am trying to develop Rician fading channel simulator in LabVIEW, but I ran into some problems. I have complex sinusoid as my line-of-signs signal. ...
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1answer
170 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 ...
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0answers
18 views

Simulating rain interference

What fading model should I use for simulating rain loss in my network simulations? I am using NS-3 for this and I'm quite lost on how to go about this. My simulation is just simple packet streaming ...