Removed directivity index

Signed-off-by: Aditya <[email protected]>

examples/worlds/acoustic_comms_propagation.sdf

@@ -32,7 +32,6 @@
  <propagation_model>
  <source_power>0.001</source_power>
  <noise_level>150</noise_level>
- <directivity_index>4</directivity_index>
  <spectral_efficiency>7</spectral_efficiency>
  </propagation_model>
 

src/systems/acoustic_comms/AcousticComms.cc

@@ -76,11 +76,6 @@ class AcousticComms::Implementation
  /// receiver to the same reference intensity used for source level.
  public: double noiseLevel = 1;
 
- /// \brief Ratio of the total noise power at the array to the
- /// noise received by the array along its main response axis.
- /// \ref https://ieeexplore.ieee.org/document/5664178
- public: double directivityIndex = 4;
-
  /// \brief Information rate that can be transmitted over a given
  /// bandwidth in a specific communication system, in (bits/sec)/Hz.
  /// \ref: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5514747/
@@ -104,15 +99,14 @@ bool AcousticComms::Implementation::propagationModel(
  // converted to dB.
  // TL : Transmission loss (dB)
  // NL : Noise level.
- // DI : Receiver directivity index.
 
  // The constant 170.8 comes from reference intensity measured
  // 1m from the source.
  double sl = 170.8 + 10 * std::log10(this->sourcePower);
  double tl = 20 * std::log10(_distToSource);
 
  // Calculate SNR.
- auto snr = sl - tl - (this->noiseLevel - this->directivityIndex);
+ auto snr = sl - tl - this->noiseLevel;
 
  // References : https://www.montana.edu/aolson/ee447/EB%20and%20NO.pdf
  // https://en.wikipedia.org/wiki/Eb/N0
@@ -169,8 +163,6 @@ void AcousticComms::Load(
  GetElement("propagation_model");
  this->dataPtr->sourcePower = propElement->Get<double>("source_power");
  this->dataPtr->noiseLevel = propElement->Get<double>("noise_level");
- this->dataPtr->directivityIndex =
- propElement->Get<double>("directivity_index");
  this->dataPtr->spectralEfficiency =
  propElement->Get<double>("spectral_efficiency");
  }

src/systems/acoustic_comms/AcousticComms.hh

@@ -69,9 +69,6 @@ namespace systems
  /// * <noise_level> : Ratio of the noise intensity at the
  /// receiver to the same reference intensity used
  /// for source level. Defaults to 1.
- /// * <directivity_index> : Ratio of the total noise power at the
- /// array to the noise received by the array
- /// along its main response axis. Defaults to 4.
  /// * <spectral_efficiency> : Information rate that can be transmitted
  /// over a given bandwidth in a specific
  /// communication system, in (bits/sec)/Hz.
@@ -91,7 +88,6 @@ namespace systems
  /// <propagation_model>
  /// <source_power>2000</source_power>
  /// <noise_level>1</noise_level>
- /// <directivity_index>4</directivity_index>
  /// <spectral_efficiency>7</spectral_efficiency>
  /// </propagation_model>
  ///