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simplify the code a bit. Make sure we handle correctly the calculation of the reference rx power

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This commit is contained in:
Mathieu Lacage
2007-11-06 10:37:12 +01:00
parent bf33ac89eb
commit f0740d8235
1 changed files with 11 additions and 18 deletions
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29
src/devices/wifi/propagation-loss-model.cc
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@@ -103,7 +103,6 @@ PropagationLossModel::CreateDefault (void)
break;
}
}
RandomPropagationLossModel::RandomPropagationLossModel ()
: m_variable (g_random.GetCopy ())
{}
@@ -196,9 +195,9 @@ FriisPropagationLossModel::GetRxPower (double txPowerDbm,
* Here, we ignore tx and rx gain and the input and output values
* are in dbm:
*
* 10 lambda^2
* rx = tx + ------- * ln (-------------------)
* ln (10) (4 * pi * d)^2 * L
* lambda^2
* rx = tx + 10 log10 (-------------------)
* (4 * pi * d)^2 * L
*
* rx: rx power (dbm)
* tx: tx power (dbm)
@@ -213,7 +212,7 @@ FriisPropagationLossModel::GetRxPower (double txPowerDbm,
}
double numerator = m_lambda * m_lambda;
double denominator = 16 * PI * PI * distance * distance * m_systemLoss;
double pr = log (numerator / denominator) * 10 / log (10);
double pr = 10 * log10 (numerator / denominator);
double rxPowerDbm = txPowerDbm + pr;
NS_LOG_DEBUG ("distance="<<distance<<"m, tx power="<<txPowerDbm<<"dbm, rx power="<<rxPowerDbm<<"dbm");
return rxPowerDbm;
@@ -264,13 +263,6 @@ LogDistancePropagationLossModel::CreateDefaultReference (void)
break;
}
}
double
LogDistancePropagationLossModel::DbToW (double db) const
{
return pow(10.0,db/10.0);
}
double
LogDistancePropagationLossModel::GetRxPower (double txPowerDbm,
@@ -278,7 +270,7 @@ LogDistancePropagationLossModel::GetRxPower (double txPowerDbm,
Ptr<MobilityModel> b) const
{
double distance = a->GetDistanceFrom (b);
if (distance <= 1.0)
if (distance <= m_referenceDistance)
{
return txPowerDbm;
}
@@ -292,14 +284,15 @@ LogDistancePropagationLossModel::GetRxPower (double txPowerDbm,
* tx: tx power (db)
* rx: db
*
* Since we use dbm instead of db, we have:
* Which, in our case is:
*
* rx = rx0 - 10 (n * log (d/d0) - ln (1000))
* rx = rx0(tx) - 10 * n * log (d/d0)
*/
static Ptr<StaticMobilityModel> zero = Create<StaticMobilityModel> (Position (0.0, 0.0, 0.0));
static Ptr<StaticMobilityModel> one = Create<StaticMobilityModel> (Position (1.0, 1.0, 1.0));
double rx0 = m_reference->GetRxPower (txPowerDbm, zero, one);
double rxPowerDbm = rx0 - 10 / log (10) * (m_exponent * log (distance / m_referenceDistance) - log (1000));
static Ptr<StaticMobilityModel> reference = Create<StaticMobilityModel> (Position (m_referenceDistance, 0.0, 0.0));
double rx0 = m_reference->GetRxPower (txPowerDbm, zero, reference);
double pathLossDb = 10 * m_exponent * log10 (distance / m_referenceDistance);
double rxPowerDbm = rx0 - pathLossDb;
NS_LOG_DEBUG ("distance="<<distance<<"m, tx-power="<<txPowerDbm<<"dbm, "<<
"reference-rx-power="<<rx0<<"dbm, "<<
"rx-power="<<rxPowerDbm<<"dbm");