Technical Question about Altair Feko API Source Code

Argianto Rahartomo

Dear Ladies and Gentlemen,

 

I have a technical question regarding the ALtair Feko API source code. 

Currently, I am investigating the output values of Field Strength when running the API of outdoorpropagation_runms. 

The output values are being printed in the result1.txt file, which corresponds to the first antenna I created. 

In the result1.txt, we can observe the Field Strength values in dB uV/m.

 

I am interested in delving deeper into how and where exactly these values are calculated. 

My primary reference points are the outdoor_propagation_runms.h and OutdoorPlugIn.h files. 

In the OutdoorPlugIn.h file, there is a section of code (lines 341-372) that appears to be related to the calculation.

 

/**

 * Computation of wave propagation prediction for a specified scenario and the specified

 * trajectories. All relevant information has to be passed to the function.

 *

 * @param [in]      ParameterAntenna    Configuration of antenna (see \ref WinProp_Antenna).

 * @param [in,out]  ParameterUrban      Configuration of scenario (see \ref WinProp_ParaMain).

 * @param [in]      ParameterModelUrban Configuration of the urban prediction model. This

 *                                      parameter is optional and depends on the selected

 *                                      prediction model:

 *                                      + Urban Dominant Path Model (see \ref Model_DPM).

 *                                      + 3D Intelligent Ray Tracing (see \ref Model_UrbanIRT).

 * @param [in]      ParameterRural      Configuration of rural prediction model. Only relevant if

 *                                      a rural prediction is done (see \ref WinProp_ParaRural).

 * @param          trajectories        The trajectories, an array of size \p nrTrajectories.

 * @param          nrTrajectories      The number of trajectories.

 * @param [in]      Callback            Configuration of callback functions (see

 *                                      WinProp_Callback). This parameter is optional.

 * @param [in,out]  resultTrajectories  Non-null, structure containing the trajectory results.

 *

 * @returns An int.

 */

 

ENGINE_API int OutdoorPlugIn_ComputeTrajectories(

    const WinProp_Antenna* ParameterAntenna,

    WinProp_ParaMain* ParameterUrban,

    const void* ParameterModelUrban,

    const WinProp_ParaRural* ParameterRural,

    const WinProp_Trajectory* trajectories,

    const int nrTrajectories,

    const WinProp_Callback* Callback,

    WinProp_ResultTrajectoryList* resultTrajectories);

 

I assume that the calculation is performed by this function, but I have yet to locate the implementation or formula used for this calculation.

I also suspect that it might be a 'closed' implementation handled by the ENGINE_API.

 

My question is how can I access the implementation and make modifications to it? 

The reason for wanting to make changes is that I have noticed inaccuracies in the Field Strength values for certain technologies like DECT NR+. 

I attempted to apply a formula adjustment: 

For channel bandwidths other than 5 MHz, a factor of 10 × log10 (channel bandwidth / 5 MHz) should be added to the field strength levels.

 

I would greatly appreciate your assistance with this matter. 

Thank you.

Jaehoon

Hello Argianto,

Unfortunately, the user is not allowed to make a correction in the WinProp API functions which compute the Rx power,  pathloss, or field strength.

Please take a look at the function in the API user guide to understand the results better. 

If you want to apply some correction factors, you can do that in a postprocessing step for the computed WinProp results obtained from the given API function (by using ProMan > Edit > Add or Subtract Data) as shown below.

Best regards,

Jaehoon