FSO fading model

[Naazira Badar]

Hi all..
Could anyone tell me which fading model should I employ for FSO if my link range is 2.5 km and I’m simulating it for all values of attenuation coefficient representing weather range of clear to thick fog?

Thanks.

[prakash jat]

hi naazira
optisystem is using gamma- gamma channel in fso component , if you want try differnt then you can use negative exponetial channel( which is also better) through matlab interfacing in optisystem

[aasif bashir dar]

hi all
some associated post with your topic are already present in form.
1.https://optiwave.com/forums/topic/fso-fading-models/

2.https://optiwave.com/forums/topic/variable-attenuation-in-a-single-fso/

hope you might get some help from these posts.

with regards

[Naazira Badar]

Thanks both you.

Prakash, I need to change just one parameter, i.e. the scintillation index of the FSO channel.Do I need to add a MATLAB module itself, or do I need to change the parameter to script mode and load it with program of any particular channel model?

[aasif bashir dar]

hi all,

i guess you can not add matlab module to it. because it is just a parameter of o FSO component. and we generally co simulated matlab with the optisystem where we make some componenent with matlab(i.e matlab component)

this matlab component can be optical or electrical or both.

with regards

[Naazira Badar]

Yes Aasif. I too think so. Thanks.

[aasif bashir dar]

hi all,

i think there may or may not script for parameter, i.e. the scintillation index.may be there could be option to attach the .dat file or text file in thee parameter window of the FSO. Be patient any one explain it soon.

with regards

[Naazira Badar]

Aasif, scintillation index parameter has an option to be changed to script mode.Could the MATLAB code for a fading model not be placed in the script?

[alistu]

Hi Naazira,

Matlab code cannot be used in the script mode. Only a relation can be used in the script mode whose answer is only one number, and not a series or a vector of numbers or an equation. And the parameters used in that relation should either be numbers or have been defined somewhere in the implementation.

Regards

[Aabid Baba]

Hello Naazira,
As for as writing Matlab code in the script is concerned , you could refer to a comment which was posted by Damian in reply to a question regarding changing the script.

apodization function using script

I hope it clears your doubts. Alistu has also explained it to the point. Hope this is helpful in some way.
Regards

[aasif bashir dar]

hi all,
this what i was talking about that we cannot make matlab module and attach it to FSO component in matlab. the link provided by aabid is the post started by me. i message damian for making reply to my post, because i had the similar problem.

you can also message him. he will provide you better suggestions

with regards

[Aabid Baba]

hello Asif,
Yeah you actually had started the topic and i had gone through your post and i just had come across this script thing mentioned by Damian.
He clearly mentions of not being able to write code in the script. But as far as i understand we can not write Matlab code in the script although we can create a MATLAB module for FSO. You are confusing yourself here. It is the code for the script we cannot write , Matlab Module we can create for FSO.
Thank you.
Regards

[Naazira Badar]

Hi..

Thanks all for your comments.
Well I understand your point. I think I can’t write MATLAB code in the script mode.But I think i should see how I can interface a MATLAB module to my FSO channel.

[Aabid Baba]

you are welcome naazira,
If you cannot figure out HOW , you are free to mail the optiwave support at support@optiwave.com.

[Naazira Badar]

hi all..
I just went through the link posted by Aabid about Aasif’s query . Well, as it is known that script can have a relation of some formula. So, I think the expression of a fading model could be put in the script itself, if it doesn’t have to be an entire MATLAB code.

Regards

[Naazira Badar]

Yes Aabid. Actually the support had mentioned about adding the component as well. But i’m confused because i have to make code of an already existing parameter of an Optiwave component variable and not actually add a new function there at.
Thanks for your help anyway.

[Aabid Baba]

Okay.
If so then you better ask Damian or Marc because they would be exactly knowing what component it is and where it is. All you would have to do then would be just changing the parameters instead of creating a new component in the MATLAB.

[Aabid Baba]

Hi naazira,
If you had noticed Alistu has mentioned in previous comment that only a relation can be used in the script mode whose answer is only one number, and not a series or a vector of numbers or an equation. You can refer to comment #30557.
So i believe it is not going to be an equation that you would be putting in the script itself.

Best Regards

[Naazira Badar]

hi Prakash, Thanks for suggesting the negative exponential model. Is it good for all turbulence conditions? Gamma-Gamma is known to be good both both strong and weak turbulence conditions.

[aasif bashir dar]

hi naazira and aabid

first i was to mention that as per marek we can use script or embbed matlab parametewr (in my query). nearly same situation is here. however in my post provided idea of attaching the .text file of the corresponding apodization function.

your query is valid and only be answered by optiwave support

with regards

[Naazira Badar]

Yeah, but I think they mentioned about adding a Component by interfacing. See actually, there is a parameter ‘Scintillation Index’ in the FSO channel’s Enhanced options. Once you enable it, Gamma-Gamma fading model gets employed. I want that once I enable, Optisystem should load the fading model of my choice. I hope my issue is more clear to you now.

Regards.

[aasif bashir dar]

i guess there is no such option as i have seen that,
still it is valid query, where should be able to change the fading models as the climate , structure , altitude of region,as defferent environment can not be modelled by the same fading models. we need different fading models to model different environmental conditions

with regards

[Naazira Badar]

yes Aasif. But i’m sure there would be a way out to this.

Regards.

[Marvi grover]

hello !!
Can anybody tell me how to code the attenuation due to scintillation effect in MATLAB. i need to use a MATLAB code and produce the same effect on the signal as done by enabling ‘intensity scintillation’ parameter in optisystem.

i shall be thankful to you
Regards
Marvi

[Naazira Badar]

Hi Marvi Grover

Well a number of discussions have already been held on to how this is supposed to be done.
you need to add a MATLAB component to your layout. Turn off intensity scintillation in FSO channel. Load your MATLAB component by program of the corresponding fading model you want to employ. You would need to mention the path of your program in MATLAB component as well.

i am posting link to a beneficial post. Here it goes : https://optiwave.com/forums/topic/log-normal-channel-in-fso

Regards
Naazira Badar

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