diff --git a/src/propagation/doc/propagation.rst b/src/propagation/doc/propagation.rst index 5e5bc9917..e9c7d12ad 100644 --- a/src/propagation/doc/propagation.rst +++ b/src/propagation/doc/propagation.rst @@ -267,21 +267,27 @@ propagation loss. NakagamiPropagationLossModel ============================ -This propagation loss model implements Nakagami-m fast fading propagation loss model. +This propagation loss model implements the Nakagami-m fast fading +model, which accounts for the variations in signal strength due to multipath +fading. The model does not account for the path loss due to the +distance traveled by the signal, hence for typical simulation usage it +is recommended to consider using it in combination with other models +that take into account this aspect. The Nakagami-m distribution is applied to the power level. The probability density function is defined as .. math:: - p(x; m, \omega) = \frac{2 m^m}{\Gamma(m) \omega^m} x^{2m - 1} e^{-\frac{m}{\omega} x^2} = 2 x \cdot p_{\text{Gamma}}(x^2, m, \frac{m}{\omega}) + p(x; m, \omega) = \frac{2 m^m}{\Gamma(m) \omega^m} x^{2m - 1} e^{-\frac{m}{\omega} x^2} ) with :math:`m` the fading depth parameter and :math:`\omega` the average received power. It is implemented by either a :cpp:class:`GammaRandomVariable` or a :cpp:class:`ErlangRandomVariable` random variable. -Like in :cpp:class:ThreeLogDistancePropagationLossModel`, the :math:`m` parameter is varied -over three distance fields: +The implementation of the model allows to specify different values of +the :math:`m` parameter (and hence different fast fading profiles) +for three different distance ranges: .. math:: diff --git a/src/propagation/model/propagation-loss-model.h b/src/propagation/model/propagation-loss-model.h index 406bbea5c..bc8f3837e 100644 --- a/src/propagation/model/propagation-loss-model.h +++ b/src/propagation/model/propagation-loss-model.h @@ -629,17 +629,24 @@ private: * \ingroup propagation * * \brief Nakagami-m fast fading propagation loss model. + * + * This propagation loss model implements the Nakagami-m fast fading + * model, which accounts for the variations in signal strength due to multipath + * fading. The model does not account for the path loss due to the + * distance traveled by the signal, hence for typical simulation usage it + * is recommended to consider using it in combination with other models + * that take into account this aspect. * * The Nakagami-m distribution is applied to the power level. The probability * density function is defined as - * \f[ p(x; m, \omega) = \frac{2 m^m}{\Gamma(m) \omega^m} x^{2m - 1} e^{-\frac{m}{\omega} x^2} = 2 x \cdot p_{\text{Gamma}}(x^2, m, \frac{m}{\omega}) \f] + * \f[ p(x; m, \omega) = \frac{2 m^m}{\Gamma(m) \omega^m} x^{2m - 1} e^{-\frac{m}{\omega} x^2} \f] * with \f$ m \f$ the fading depth parameter and \f$ \omega \f$ the average received power. * * It is implemented by either a ns3::GammaRandomVariable or a * ns3::ErlangRandomVariable random variable. * - * Like in ns3::ThreeLogDistancePropagationLossModel, the m parameter is varied - * over three distance fields: + * The implementation of the model allows to specify different values of the m parameter (and hence different fading profiles) + * for three different distance ranges: * \f[ \underbrace{0 \cdots\cdots}_{m_0} \underbrace{d_1 \cdots\cdots}_{m_1} \underbrace{d_2 \cdots\cdots}_{m_2} \infty \f] * * For m = 1 the Nakagami-m distribution equals the Rayleigh distribution. Thus