Rayleigh Fading Channe;.

[cwjcwjcwj]

I am working on rayleigh fading channel. And I have a doubt here when I am doing the modelling. Lets say, I have a complex number signal A+j*B, which is going thru a fading channel(Ignore noise here for simplification), and of cause the complex rayleigh variable which is Z+j*Y. My question is, which one of the following method is correct?

1) Channel output= (Z*A)+j*(Y*B)

OR

2) Channel output= (A+j*B)(Z+j*Y)=A*Z+j*Y*A+j*B*Z-B*Y

or both of them also correct? Pls help to clarify?

 

[qiqi6416]

hi, there,I don't think the mentioned two soulutions are correct..in my opinion, the Rayleigh channel should be modelled in frequency domain rather than time domain. Therefore, convolution should be applied when signal go through the channel.

 

[cwjcwjcwj]

This is the way in which is used by 'purely' coded system or coded modulation system(regardless of multicarrier system). My doubt is, which one is the correct way to implement this? Any others suggestions?

 

[oz]

option 2

 

[bulx]

rayleigh fading is a multiplicative effect (in contrast classic AWGN, which is your first choice), so option2 is correct.

Of course, if you are in log scale for some numerical calculation, addition is to be used.
-b

 

[ahmed1]

Hi dear
opation 2 is correct

 

[yanghui_1231]

2,but Rayleigh Fading Channe is a multipath channel module.

 

[music_lover04]

If you want to see some sample code u can look into this website:

https://www.mathworks.com/matlabcen...bjectId=63&objectName=Wireless Communications

 

[spweda]

Method 1 is correct since the I and Q care independent. You just need to filter the I and Q signal.

 

[amihomo]

method 1 is incorrect ,since if Z+j*Y is a complex rayleigh variable ,then Z and Y have guassian distribution.and the net effect of multiplicative distortion has not a rayliegh distribution.
method 2 seems to be correct.

 

[tarakapraveen]

Method 2 is some wht correct but the rayleigh fading effect (Multi path fading ) seeming to me multiplication in case single path case .In case of Multiple paths it should be CONVOLUTION(also multiplication but delay is involved).

So Rayleigh fading =>convoluted with the signal

AWGN =>Addition with the signal

Regards
Goud

 

[amihomo]

Method 2 is some wht correct but the rayleigh fading effect (Multi path fading ) seeming to me multiplication in case single path case .In case of Multiple paths it should be CONVOLUTION(also multiplication but delay is involved).

So Rayleigh fading =>convoluted with the signal

AWGN =>Addition with the signal

Regards
Goud

Hi tarakapraveen ,
rayleigh fading is not convolution.
Essentially a multipath fading channel is modeled as a tapped delay line with tap coefficients which are random variables having rayleigh distributions.
and as any other linear channel , the output of channel equals to the convolution of channel's impulse response with the input signal .


regards

 

[music_lover04]

please look into RAPPAPORT page 220 i think that will help u understand the topic better

 

[grab]

i need a matlab code to simulate the rayleigh effect in channel and adding of noise

 

[yella]

www.dsplog.com site's code is very better than this one....

 

[Tamas888]

hello everybody.
I ask here because you may know Rayleigh fading well.. I use that formula where the probability depends on the transmit power.. I use sensors (i.e. MICA2) and want to know what is the connection between the above transmit power and the used current during the activity.. because I want to simulate the power consumption and the errors at the same time.
thanks!! Tamas

 

[Ahmed Alaa]

Option 2 is the correct one, but if you're using the log scale, consider option 1.