From 568cd20be1fe456509b49f10ae749400cc03a79c Mon Sep 17 00:00:00 2001 From: Nicola Baldo Date: Tue, 7 May 2013 18:57:51 +0200 Subject: [PATCH] fixed bug 1421 - Frequency dependent propagation loss models need uniform Frequency / Lambda attribute --- CHANGES.html | 8 +++ RELEASE_NOTES | 1 + .../model/propagation-loss-model.cc | 58 +++++++++---------- .../model/propagation-loss-model.h | 48 +++++++-------- .../test/propagation-loss-model-test-suite.cc | 10 ++-- 5 files changed, 68 insertions(+), 57 deletions(-) diff --git a/CHANGES.html b/CHANGES.html index 37afa13cb..0f36c9e70 100644 --- a/CHANGES.html +++ b/CHANGES.html @@ -88,6 +88,14 @@ us a note on ns-developers mailing list.

  • New Tag, PacketSocketTag, to carry the dest address of a packet and the packet type
  • New Tag, DeviceNameTag, to carry the ns3 device name from where a packet is coming
  • New Error Model, BurstError model, to determine which bursts of packets are errored corresponding to an underlying distribution, burst rate, and burst size
    • +
  • To make the API more uniform across the various + PropagationLossModel classes, the Set/GetLambda methods of the + FriisPropagationLossModel and TwoRayGroundPropagationLossModel + classes have been changed to Set/GetFrequency, and now a Frequency + attribute is exported which replaces the pre-existing Lambda + attribute. Any previous user code setting a value for Lambda should + be changed to set instead a value of Frequency = C / Lambda, with C + = 299792458.0.

    • Changes to existing API:

    diff --git a/RELEASE_NOTES b/RELEASE_NOTES index 005773343..028c453cd 100644 --- a/RELEASE_NOTES +++ b/RELEASE_NOTES @@ -38,6 +38,7 @@ Bugs fixed - bug 1256 - Unnecessary SND.NXT advance, missing ACK for Out of Order segments - bug 1318 - Ipv6L3Protocol::LocalDeliver can get stuck in an infinte loop - bug 1409 - Add an attribute "SystemId" to configure the ID for MPI +- bug 1421 - Frequency dependent propagation loss models need uniform Frequency / Lambda attribute - bug 1434 - DSR throughput not comparable to other protocols for manet example - bug 1502 - Shutdown on tcp socket seems to misbehave - bug 1503 - BlockAckManager infine loop diff --git a/src/propagation/model/propagation-loss-model.cc b/src/propagation/model/propagation-loss-model.cc index 5c06cab19..f52c66a06 100644 --- a/src/propagation/model/propagation-loss-model.cc +++ b/src/propagation/model/propagation-loss-model.cc @@ -148,10 +148,11 @@ FriisPropagationLossModel::GetTypeId (void) static TypeId tid = TypeId ("ns3::FriisPropagationLossModel") .SetParent () .AddConstructor () - .AddAttribute ("Lambda", - "The wavelength (default is 5.15 GHz at 300 000 km/s).", - DoubleValue (300000000.0 / 5.150e9), - MakeDoubleAccessor (&FriisPropagationLossModel::m_lambda), + .AddAttribute ("Frequency", + "The carrier frequency (in Hz) at which propagation occurs (default is 5.15 GHz).", + DoubleValue (5.150e9), + MakeDoubleAccessor (&FriisPropagationLossModel::SetFrequency, + &FriisPropagationLossModel::GetFrequency), MakeDoubleChecker ()) .AddAttribute ("SystemLoss", "The system loss", DoubleValue (1.0), @@ -190,20 +191,19 @@ FriisPropagationLossModel::GetMinDistance (void) const { return m_minDistance; } + void -FriisPropagationLossModel::SetLambda (double frequency, double speed) +FriisPropagationLossModel::SetFrequency (double frequency) { - m_lambda = speed / frequency; -} -void -FriisPropagationLossModel::SetLambda (double lambda) -{ - m_lambda = lambda; + m_frequency = frequency; + static const double C = 299792458.0; // speed of light in vacuum + m_lambda = C / frequency; } + double -FriisPropagationLossModel::GetLambda (void) const +FriisPropagationLossModel::GetFrequency (void) const { - return m_lambda; + return m_frequency; } double @@ -285,10 +285,11 @@ TwoRayGroundPropagationLossModel::GetTypeId (void) static TypeId tid = TypeId ("ns3::TwoRayGroundPropagationLossModel") .SetParent () .AddConstructor () - .AddAttribute ("Lambda", - "The wavelength (default is 5.15 GHz at 300 000 km/s).", - DoubleValue (300000000.0 / 5.150e9), - MakeDoubleAccessor (&TwoRayGroundPropagationLossModel::m_lambda), + .AddAttribute ("Frequency", + "The carrier frequency (in Hz) at which propagation occurs (default is 5.15 GHz).", + DoubleValue (5.150e9), + MakeDoubleAccessor (&TwoRayGroundPropagationLossModel::SetFrequency, + &TwoRayGroundPropagationLossModel::GetFrequency), MakeDoubleChecker ()) .AddAttribute ("SystemLoss", "The system loss", DoubleValue (1.0), @@ -337,20 +338,19 @@ TwoRayGroundPropagationLossModel::SetHeightAboveZ (double heightAboveZ) { m_heightAboveZ = heightAboveZ; } -void -TwoRayGroundPropagationLossModel::SetLambda (double frequency, double speed) + +void +TwoRayGroundPropagationLossModel::SetFrequency (double frequency) { - m_lambda = speed / frequency; + m_frequency = frequency; + static const double C = 299792458.0; // speed of light in vacuum + m_lambda = C / frequency; } -void -TwoRayGroundPropagationLossModel::SetLambda (double lambda) + +double +TwoRayGroundPropagationLossModel::GetFrequency (void) const { - m_lambda = lambda; -} -double -TwoRayGroundPropagationLossModel::GetLambda (void) const -{ - return m_lambda; + return m_frequency; } double @@ -415,7 +415,7 @@ TwoRayGroundPropagationLossModel::DoCalcRxPower (double txPowerDbm, * */ - double dCross = (4 * PI * txAntHeight * rxAntHeight) / GetLambda (); + double dCross = (4 * PI * txAntHeight * rxAntHeight) / m_lambda; double tmp = 0; if (distance <= dCross) { diff --git a/src/propagation/model/propagation-loss-model.h b/src/propagation/model/propagation-loss-model.h index fc6d5a73d..960b8f95a 100644 --- a/src/propagation/model/propagation-loss-model.h +++ b/src/propagation/model/propagation-loss-model.h @@ -171,6 +171,11 @@ private: * This model is invalid for small distance values. * The current implementation returns the txpower as the rxpower * for any distance smaller than MinDistance. + * + * In the implementation, \f$ \lambda \f$ is calculated as + * \f$ \frac{C}{f} \f$, where \f$ C = 299792458\f$ m/s is the speed of light in + * vacuum, and \f$ f \f$ is the frequency in Hz which can be configured by + * the user via the Frequency attribute. */ class FriisPropagationLossModel : public PropagationLossModel { @@ -179,19 +184,11 @@ public: FriisPropagationLossModel (); /** * \param frequency (Hz) - * \param speed (m/s) * - * Set the main wavelength used in the Friis model + * Set the carrier frequency used in the Friis model * calculation. */ - void SetLambda (double frequency, double speed); - /** - * \param lambda (m) the wavelength - * - * Set the main wavelength used in the Friis model - * calculation. - */ - void SetLambda (double lambda); + void SetFrequency (double frequency); /** * \param systemLoss (dimension-less) * @@ -213,9 +210,9 @@ public: double GetMinDistance (void) const; /** - * \returns the current wavelength (m) + * \returns the current frequency (Hz) */ - double GetLambda (void) const; + double GetFrequency (void) const; /** * \returns the current system loss (dimension-less) */ @@ -233,6 +230,7 @@ private: static const double PI; double m_lambda; + double m_frequency; double m_systemLoss; double m_minDistance; }; @@ -259,27 +257,26 @@ private: * The crossover distance, below which Friis is used, is calculated as follows: * * \f$ dCross = \frac{(4 * pi * Ht * Hr)}{lambda} \f$ + * + * In the implementation, \f$ \lambda \f$ is calculated as + * \f$ \frac{C}{f} \f$, where \f$ C = 299792458\f$ m/s is the speed of light in + * vacuum, and \f$ f \f$ is the frequency in Hz which can be configured by + * the user via the Frequency attribute. */ class TwoRayGroundPropagationLossModel : public PropagationLossModel { public: static TypeId GetTypeId (void); TwoRayGroundPropagationLossModel (); + /** * \param frequency (Hz) - * \param speed (m/s) * - * Set the main wavelength used in the TwoRayGround model + * Set the carrier frequency used in the TwoRayGround model * calculation. */ - void SetLambda (double frequency, double speed); - /** - * \param lambda (m) the wavelength - * - * Set the main wavelength used in the TwoRayGround model - * calculation. - */ - void SetLambda (double lambda); + void SetFrequency (double frequency); + /** * \param systemLoss (dimension-less) * @@ -297,10 +294,12 @@ public: * \returns the minimum distance. */ double GetMinDistance (void) const; + /** - * \returns the current wavelength (m) + * \returns the current frequency (Hz) */ - double GetLambda (void) const; + double GetFrequency (void) const; + /** * \returns the current system loss (dimension-less) */ @@ -324,6 +323,7 @@ private: static const double PI; double m_lambda; + double m_frequency; double m_systemLoss; double m_minDistance; double m_heightAboveZ; diff --git a/src/propagation/test/propagation-loss-model-test-suite.cc b/src/propagation/test/propagation-loss-model-test-suite.cc index c7c130886..06bcf13c1 100644 --- a/src/propagation/test/propagation-loss-model-test-suite.cc +++ b/src/propagation/test/propagation-loss-model-test-suite.cc @@ -68,8 +68,9 @@ FriisPropagationLossModelTestCase::DoRun (void) // The ns-3 testing manual gives more background on the values selected // for this test. First, set a few defaults. - // wavelength at 2.4 GHz is 0.125m - Config::SetDefault ("ns3::FriisPropagationLossModel::Lambda", DoubleValue (0.125)); + // the test vectors have been determined for a wavelength of 0.125 m + // which corresponds to a frequency of 2398339664.0 Hz in the vacuum + Config::SetDefault ("ns3::FriisPropagationLossModel::Frequency", DoubleValue (2398339664.0)); Config::SetDefault ("ns3::FriisPropagationLossModel::SystemLoss", DoubleValue (1.0)); // Select a reference transmit power @@ -164,8 +165,9 @@ TwoRayGroundPropagationLossModelTestCase::~TwoRayGroundPropagationLossModelTestC void TwoRayGroundPropagationLossModelTestCase::DoRun (void) { - // wavelength at 2.4 GHz is 0.125m - Config::SetDefault ("ns3::TwoRayGroundPropagationLossModel::Lambda", DoubleValue (0.125)); + // the test vectors have been determined for a wavelength of 0.125 m + // which corresponds to a frequency of 2398339664.0 Hz in the vacuum + Config::SetDefault ("ns3::TwoRayGroundPropagationLossModel::Frequency", DoubleValue (2398339664.0)); Config::SetDefault ("ns3::TwoRayGroundPropagationLossModel::SystemLoss", DoubleValue (1.0)); // set antenna height to 1.5m above z coordinate