# Multipath Fading

**URL:** <https://www.ruby-forum.com/t/multipath-fading/241708>\
**Category:** GNU Radio\
**Created:** [April 25, 2015, 1:41pm UTC](https://www.ruby-forum.com/t/multipath-fading/241708 "2015-04-25T13:41:13Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [April 25, 2015, 1:41pm UTC](https://www.ruby-forum.com/t/multipath-fading/241708/1 "2015-04-25T13:41:13Z")

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Dear Sir/Mam,

Hello, i am a student working on the development of a channel emulator,  
Can  
you tell me how can you make one in GNU Radio?

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**Author:** ![Ritvik\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/df705f/32.png) [@Ritvik\_P](https://www.ruby-forum.com/u/Ritvik_P)\
**Post date:** [April 25, 2015, 1:45pm UTC](https://www.ruby-forum.com/t/multipath-fading/241708/2 "2015-04-25T13:45:48Z")

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Regarding my last post i want to bring it to your notice that i have to  
implement a multipath fading channel emulator so can you tell me how can  
i  
do that?

On Sat, Apr 25, 2015 at 5:03 PM, Ritvik P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)

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**Author:** ![Ritvik\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/df705f/32.png) [@Ritvik\_P](https://www.ruby-forum.com/u/Ritvik_P)\
**Post date:** [April 25, 2015, 2:42pm UTC](https://www.ruby-forum.com/t/multipath-fading/241708/3 "2015-04-25T14:42:09Z")

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On 04/25/2015 07:36 AM, Ritvik P. wrote:

> ```
> emulator, Can you tell me how can you make one in GNU Radio?
> 
> ```
> 
> * * *
> 
> Discuss-gnuradio mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)

Take a look at the blocks in GRC under “Channel Models”. It looks like  
static multipath fading is handled/approximated by a couple of the  
blocks there.

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<div class="post-metadata">

**Author:** ![Ritvik\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/df705f/32.png) [@Ritvik\_P](https://www.ruby-forum.com/u/Ritvik_P)\
**Post date:** [April 25, 2015, 4:11pm UTC](https://www.ruby-forum.com/t/multipath-fading/241708/4 "2015-04-25T16:11:33Z")

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Hi Ritvik,

also notice that you might want to have a look at how things are done in  
GNU Radio generally:  
[https://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorials](https://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials)

I really recommend reading part 1 to 5.

Greetings,  
Marcus

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**Author:** ![Ritvik\_P](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/df705f/32.png) [@Ritvik\_P](https://www.ruby-forum.com/u/Ritvik_P)\
**Post date:** [April 26, 2015, 12:13pm UTC](https://www.ruby-forum.com/t/multipath-fading/241708/5 "2015-04-26T12:13:12Z")

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I think this block is just a single tap channel. If you want to have  
multipath channel use channel\_model2 instead:

> **[GNU Radio Manual and C++ API Reference: gr::channels::channel\_model2 Class...](https://www.gnuradio.org/doc/doxygen/classgr_1_1channels_1_1channel__model2.html)**

Best,  
Mostafa

On Sat, Apr 25, 2015 at 8:44 PM, Ritvik P. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> > time variation of the power of the signal (i think you’re using a single  
> > K = 4
> > 
> > > > seems almost the same. Can you guide to the mathematical model of the
> > > > 
> > > > > If you have enough background knowledge you need classify channels as
> > > > > 
> > > > > > > Dear Sir/Mam,
> > > > > 
> > > > > IRAN  
> > > > > Tel: +98 (919) 158-7730  
> > > > > LAB: [http://ele.aut.ac.ir/~mmwcl/?page\_id=411](http://ele.aut.ac.ir/~mmwcl/?page_id=411)  
> > > > > Homepage: [http://ele.aut.ac.ir/~alizadeh/](http://ele.aut.ac.ir/~alizadeh/)
> > > > > 
> > > > > * * *

–

* * *

Department of Electrical Engineering  
Aboureyhan Building  
MMWCL LAB  
Amirkabir University Of Technology  
Tehran  
IRAN  
Tel: +98 (919) 158-7730  
LAB: [http://ele.aut.ac.ir/~mmwcl/?page\_id=411](http://ele.aut.ac.ir/~mmwcl/?page_id=411)  
Homepage: [http://ele.aut.ac.ir/~alizadeh/](http://ele.aut.ac.ir/~alizadeh/)

* * *