2D Multiwall model

A fast implementation of the Multiwall model

Description

Compute 2D - MultiWall model
 
Usage
------
 
rs_amp = multiwall_model(TXpoint , RXpoint , walls , material , [L0] , [n]);
 
 
Inputs
-------
 
TXpoint Transmitter points (2 x Nt)
RXpoint Receiver points (2 x Nr)
walls Walls (4 x nwall) where [xi,0 ; yi,0 ; xi,1 ; yi,1] are coordinates of the i'th wall, i = 1,...,nwall.
material Material (2 x nwall) where [typei ; ni] reprensents type of wall and associated attenuation index, i = 1,...,nwall.
L0 Reference loss value at 1m (L0 = 40.2 default)
n Power decay factor (n = 2 default)
 
Outputs
-------
rs_amp Total power (Nt x Nr)

Compilation instruction : Please run mexme_multiwall_model
------------------------------

Run mexme_multiwall_model for compile the mex file (please be sure that mex -setup is ok on your platform).

Run test_multiwall_model for demo.

Please open multiwall_model.c for other examples

• MATLAB release: MATLAB 7.5 (R2007b)
• Other requirements: A C compiler (At least included LCC compiler)

[yon]

hi
please how i make the (data_mw), the file appeare as winap medea player file.can you clear me that?

so thanks.

[Sebastien Paris]

I don't understand your question. You have just to run the demo file 'test_multiwall_model.m'. data_mw is matlab data file. You can load it with the command load.

[Bing]

Hello,
there is a problem,
??? Undefined function or variable 'getpts'.

Error in ==> test_multiwall_model at 27
[x , y] = getpts;

pls help,thank u

[Sebastien Paris]

Ok, the getpts function is from the image processing toolbox. There are plenty of similar functions in the FEX.

[Mohd Sharim]

Hello Mr. Sebatien Paris,

I'm interested with the 2D Multiwall Model. Here Im just curious about the reference value and power factor decay that you used. May I know which propagation model that you referred for both of the values.

Thank You,

sincerely Yours,

Sharim

[Sebastien Paris]

Please open the *.c file and find the quoted reference.

[Mohd Sharim]

Hello Mr. Sebastien Paris,

Thank you for your help regarding to my last question. Now I need your help to study path loss characteristic in 2D database. Here I got a 2D database. When I tried to load the database base using 'imread' command and then load the file in your multiwall model, MATLAB unable to load the file. So, if you have any idea regarding to this post, please help me Sir.

Thank You,

Sincerely Yours,

Sharim

[Mohd Sharim]

Hello Sir,

Can you please explain me for the usage of the .mw* file in MATLAB. Thanks

[Ben Jones]

To get it to work I had to change line 132 in multiwall_model.c from

#define MAX(a , b) ((a) >= (b) ? (a) : (b))

to

#define max(a , b) ((a) >= (b) ? (a) : (b))

[Sebastien Paris]

Ho yeah, it's true .... Update with this minor bug, thx you.

[michael]

Sebastien,

can you please explain the mathematics behind the multi-wall model in your C file?
i know that it counts walls,
but how do you check that you pass them?

thank you

[Sebastien Paris]

There is a reference in the top of the C-fille...

Regards,

[kimo]

Hi,
Can you tell us please if the reflection, diffraction and refraction phenomena are taken into account?
Thanks for responding
Kimo

[kimo]

Hello again,
sorry but I figured out that the answer was NO.
I have two more questions please.
- Is it possible to take these phenomena easily and efficacely?
- Is the choice of the material matrix dimension (2*N) going in this direction (rather than (1*N))?
Thanks for your response and this vgood file.
Regards,

[Sebastien Paris]

For a more complete modelization, please have a look to :

http://www.mathworks.com/matlabcentral/fileexchange/21149-particle-filter-for-robot-localization-using-wifi-measurements

[Tanyer Alan]

 

[Jachym]

Hi Sebastien, thanks for your model. I would like to use it with my small floorplan (for my school work). Which file should I edit to define own walls place and walls materils?
I didn't find manual or something else about model.
Thanks
Jachym

[Sebastien Paris]

Jachym: you have to fill according to your floorplan variables :

1) walls (4 x nwall) where [xi,0 ; yi,0 ; xi,1 ; yi,1] are coordinates of the i'th wall, i = 1,...,nwall.
 
2) material (2 x nwall) where [typei ; ni] reprensents type of wall and associated attenuation index, i = 1,...,nwall.

This part is the most boring to do from a floorplan.

[midavisdj]

Hi Sebastien

I need to know if I can use an image (.jpg) and use it as background.

[Sebastien Paris]

midavisdj,

No you can't process like directly. You must to some image processing to extract walls from your floorplan ....

[Faisol Riza]

Hello Mr. Sebastien,

I wonder how you set the parameter of L0=40.2 in the m file. Whereas in the reference you attach in C file, it say 47,4. It is very helpfull if you would explain it.

Thank you very much

[Sebastien Paris]

Faisol... Can't tell you, I can't remember this detail.

[Faisol Riza]

It's ok then. Btw thank you very much. Your work is so good.

[Sebastien Paris]

Thanks u. A small update with openMP support will be published soon.

[Gowrishankar S]

Dear All,

 I'm getting the following error while compiling the multiwall_model.c file. Can anyone give me some pointer on how to rectify this error?

Thanks in advance

mex multiwall_model.c
lcc preprocessor warning: multiwall_model.c:241 Unknown preprocessor control endifs
lcc preprocessor error: multiwall_model.c:289 Unterminated #if/#ifdef/#ifndef
Warning multiwall_model.c: 236 local `double u' is not referenced
Warning multiwall_model.c: 236 local `double t' is not referenced
Warning multiwall_model.c: 236 local `double dy' is not referenced
Warning multiwall_model.c: 236 local `double dx' is not referenced
Warning multiwall_model.c: 236 local `double by' is not referenced
Warning multiwall_model.c: 236 local `double bx' is not referenced
Warning multiwall_model.c: 236 local `double cy' is not referenced
Warning multiwall_model.c: 236 local `double cx' is not referenced
Warning multiwall_model.c: 236 local `double denom' is not referenced
Warning multiwall_model.c: 235 local `double L' is not referenced
Warning multiwall_model.c: 235 local `double Lfsl' is not referenced
Warning multiwall_model.c: 235 local `double disttr' is not referenced
Warning multiwall_model.c: 234 local `double y4' is not referenced
Warning multiwall_model.c: 234 local `double y3' is not referenced
Warning multiwall_model.c: 234 local `double y2' is not referenced
Warning multiwall_model.c: 234 local `double _y1' is not referenced
Warning multiwall_model.c: 234 local `double x4' is not referenced
Warning multiwall_model.c: 234 local `double x3' is not referenced
Warning multiwall_model.c: 234 local `double x2' is not referenced
Warning multiwall_model.c: 234 local `double x1' is not referenced
Warning multiwall_model.c: 233 local `int iNt' is not referenced
Warning multiwall_model.c: 233 local `int kd' is not referenced
Warning multiwall_model.c: 233 local `int jd' is not referenced
Warning multiwall_model.c: 233 local `int id' is not referenced
Warning multiwall_model.c: 232 local `int k' is not referenced
Warning multiwall_model.c: 232 local `int j' is not referenced
Warning multiwall_model.c: 232 local `int i' is not referenced
Error multiwall_model.c: 288 syntax error; found `end of input' expecting `}'
2 errors, 28 warnings
 
  C:\PROGRA~1\MATLAB\R2007A\BIN\MEX.PL: Error: Compile of 'multiwall_model.c' failed.

[Sebastien Paris]

Gowrishankar,

Please change your C compiler. You can use the free MSVC express from Microsoft. Please refer which MSCV express you can use according to you current Matlab version