return m_totalEnergyConsumption;

  Time duration = Simulator::Now () - m_lastUpdateTime;

  double energyToDecrease = 0.0;

  double supplyVoltage = m_source->GetSupplyVoltage ();

  energyToDecrease = duration.GetSeconds () * m_actualCurrentA * supplyVoltage;

  m_source->UpdateEnergySource ();

  return m_totalEnergyConsumption + energyToDecrease;

  return m_totalEnergyConsumption;

  Time duration = Simulator::Now () - m_lastUpdateTime;

  NS_ASSERT (duration.GetNanoSeconds () >= 0); // check if duration is valid

  // energy to decrease = current * voltage * time

  double energyToDecrease = 0.0;

  double supplyVoltage = m_source->GetSupplyVoltage ();

  switch (m_currentState)

    {

    case WifiPhy::IDLE:

      energyToDecrease = duration.GetSeconds () * m_idleCurrentA * supplyVoltage;

      break;

    case WifiPhy::CCA_BUSY:

      energyToDecrease = duration.GetSeconds () * m_ccaBusyCurrentA * supplyVoltage;

      break;

    case WifiPhy::TX:

      energyToDecrease = duration.GetSeconds () * m_txCurrentA * supplyVoltage;

      break;

    case WifiPhy::RX:

      energyToDecrease = duration.GetSeconds () * m_rxCurrentA * supplyVoltage;

      break;

    case WifiPhy::SWITCHING:

      energyToDecrease = duration.GetSeconds () * m_switchingCurrentA * supplyVoltage;

      break;

    case WifiPhy::SLEEP:

      energyToDecrease = duration.GetSeconds () * m_sleepCurrentA * supplyVoltage;

      break;

    default:

      NS_FATAL_ERROR ("WifiRadioEnergyModel:Undefined radio state: " << m_currentState);

    }

  // notify energy source

  m_source->UpdateEnergySource ();

  return m_totalEnergyConsumption + energyToDecrease;