lorawan-mac-end-device-class-a.cc

Go to the documentation of this file.

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2017 University of Padova
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Davide Magrin <magrinda@dei.unipd.it>
 *         Martina Capuzzo <capuzzom@dei.unipd.it>
 *
 * Modified by: Peggy Anderson <peggy.anderson@usask.ca>
 *              qiuyukang <b612n@qq.com>
 *              Bastien Tauran <bastien.tauran@viveris.fr>
 */
 
#include "lorawan-mac-end-device-class-a.h"
 
#include "lora-tag.h"
#include "lorawan-mac-end-device.h"
#include "satellite-lorawan-net-device.h"
#include "satellite-phy.h"
 
#include <ns3/log.h>
#include <ns3/pointer.h>
 
#include <algorithm>
 
namespace ns3
{
 
NS_LOG_COMPONENT_DEFINE("LorawanMacEndDeviceClassA");
 
NS_OBJECT_ENSURE_REGISTERED(LorawanMacEndDeviceClassA);
 
TypeId
LorawanMacEndDeviceClassA::GetTypeId(void)
{
    static TypeId tid =
        TypeId("ns3::LorawanMacEndDeviceClassA")
            .SetParent<LorawanMacEndDevice>()
            .AddAttribute("FirstWindowDelay",
                          "Time to wait between end of message transmission and opening of first "
                          "reception window",
                          TimeValue(Seconds(1)),
                          MakeTimeAccessor(&LorawanMacEndDeviceClassA::m_firstWindowDelay),
                          MakeTimeChecker())
            .AddAttribute("SecondWindowDelay",
                          "Time to wait between end of message transmission and opening of second "
                          "reception window",
                          TimeValue(Seconds(2)),
                          MakeTimeAccessor(&LorawanMacEndDeviceClassA::m_secondWindowDelay),
                          MakeTimeChecker())
            .AddAttribute("FirstWindowDuration",
                          "Duration of first reception window",
                          TimeValue(MilliSeconds(100)),
                          MakeTimeAccessor(&LorawanMacEndDeviceClassA::m_firstWindowDuration),
                          MakeTimeChecker())
            .AddAttribute("SecondWindowDuration",
                          "Duration of second reception window",
                          TimeValue(MilliSeconds(100)),
                          MakeTimeAccessor(&LorawanMacEndDeviceClassA::m_secondWindowDuration),
                          MakeTimeChecker())
            .AddConstructor<LorawanMacEndDeviceClassA>();
    return tid;
}
 
LorawanMacEndDeviceClassA::LorawanMacEndDeviceClassA()
{
    NS_FATAL_ERROR("Default constructor not in use");
}
 
LorawanMacEndDeviceClassA::LorawanMacEndDeviceClassA(uint32_t satId,
                                                     uint32_t beamId,
                                                     Ptr<SatSuperframeSeq> seq)
    : LorawanMacEndDevice(satId, beamId),
      m_superframeSeq(seq),
      m_firstWindowDelay(Seconds(1)),
      m_secondWindowDelay(Seconds(2)),
      m_firstWindowDuration(MilliSeconds(100)),
      m_secondWindowDuration(MilliSeconds(100)),
      m_rx1DrOffset(0)
{
    NS_LOG_FUNCTION(this);
 
    // Void the two receiveWindow events
    m_closeFirstWindow = EventId();
    m_closeFirstWindow.Cancel();
    m_closeSecondWindow = EventId();
    m_closeSecondWindow.Cancel();
    m_secondReceiveWindow = EventId();
    m_secondReceiveWindow.Cancel();
}
 
LorawanMacEndDeviceClassA::~LorawanMacEndDeviceClassA()
{
    NS_LOG_FUNCTION_NOARGS();
}
 
// Sending methods //
 
void
LorawanMacEndDeviceClassA::SendToPhy(Ptr<Packet> packetToSend)
{
    // Add headers, prepare TX parameters and send the packet
    NS_LOG_FUNCTION(this);
 
    NS_LOG_DEBUG("PacketToSend: " << packetToSend);
 
    if (DynamicCast<SatLoraPhyTx>(m_phy->GetPhyTx())->IsTransmitting())
    {
        // Device already transmitting!
        NS_LOG_WARN("End Device is already transmitting. Aborting.");
        return;
    }
 
    // Data Rate Adaptation as in LoRaWAN specification, V1.0.2 (2016)
    if (m_enableDRAdapt && (m_dataRate > 0) && (m_retxParams.retxLeft < m_maxNumbTx) &&
        (m_retxParams.retxLeft % 2 == 0))
    {
        m_txPower = 14; // Reset transmission power
        m_dataRate = m_dataRate - 1;
    }
 
    if (m_isStatisticsTagsEnabled)
    {
        SatMacTimeTag satMacTag;
        packetToSend->RemovePacketTag(
            satMacTag); // If packet is retransmitted, it already has a tag, updating it
        packetToSend->AddPacketTag(SatMacTimeTag(Simulator::Now()));
 
        // Add a SatAddressTag tag with this device's address as the source address.
        packetToSend->AddByteTag(SatAddressTag(m_nodeInfo->GetMacAddress()));
 
        // Add a SatDevTimeTag tag for packet delay computation at the receiver end.
        SatDevTimeTag satDevTag;
        packetToSend->RemovePacketTag(satDevTag);
        packetToSend->AddPacketTag(SatDevTimeTag(Simulator::Now()));
    }
 
    uint32_t allocationChannel = 0; // TODO is really zero here ?
    Ptr<SatSuperframeConf> superframeConf =
        m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE);
    uint8_t frameId = superframeConf->GetRaChannelFrameId(allocationChannel);
    Ptr<SatFrameConf> frameConf = superframeConf->GetFrameConf(frameId);
    Ptr<SatTimeSlotConf> timeSlotConf = frameConf->GetTimeSlotConf(0);
    Ptr<SatWaveform> wf =
        m_superframeSeq->GetWaveformConf()->GetWaveform(timeSlotConf->GetWaveFormId());
 
    SatSignalParameters::txInfo_s txInfo;
    txInfo.modCod = wf->GetModCod();
    txInfo.fecBlockSizeInBytes = wf->GetPayloadInBytes();
    txInfo.packetType = m_packetType;
    txInfo.frameType = SatEnums::UNDEFINED_FRAME;
    txInfo.waveformId = wf->GetWaveformId();
    // txInfo.crdsaUniquePacketId = m_crdsaUniquePacketId; // reuse the crdsaUniquePacketId to
    // identify ESSA frames
 
    // Craft LoraTxParameters object
    LoraTxParameters params;
    params.sf = GetSfFromDataRate(m_dataRate);
    params.headerDisabled = m_headerDisabled;
    params.codingRate = SatUtils::GetCodingRate(wf->GetModCod());
    params.bandwidthHz = GetBandwidthFromDataRate(m_dataRate);
    params.nPreamble = m_nPreambleSymbols;
    params.crcEnabled = 1;
    params.lowDataRateOptimizationEnabled = 0;
 
    // Pick a channel on which to transmit the packet
    Ptr<LoraLogicalChannel> txChannel = GetChannelForTx();
    double frequency = txChannel->GetFrequency();
    LoraTag tag;
    packetToSend->RemovePacketTag(tag);
    tag.SetFrequency(frequency);
    tag.SetDataRate(m_dataRate);
    tag.SetModcod(wf->GetModCod());
    packetToSend->AddPacketTag(tag);
 
    SatMacTag mTag;
    packetToSend->RemovePacketTag(mTag);
    mTag.SetDestAddress(m_gwAddress);
    mTag.SetSourceAddress(Mac48Address::ConvertFrom(m_device->GetAddress()));
    packetToSend->AddPacketTag(mTag);
 
    SatAddressE2ETag addressE2ETag;
    packetToSend->RemovePacketTag(addressE2ETag);
    addressE2ETag.SetE2EDestAddress(Mac48Address::GetBroadcast());
    addressE2ETag.SetE2ESourceAddress(Mac48Address::ConvertFrom(m_device->GetAddress()));
    packetToSend->AddPacketTag(addressE2ETag);
 
    SatPhy::PacketContainer_t packets;
    packets.push_back(packetToSend);
 
    uint32_t carrierId = 0;
 
    // Compute packet duration
    Time duration = GetOnAirTime(packetToSend, params);
 
    m_phyRx->SwitchToTx();
    m_phy->SendPdu(packets, carrierId, duration, txInfo);
 
    NS_LOG_DEBUG("PacketToSend: " << packetToSend);
 
    // Register packet transmission for duty cycle
 
    // Register the sent packet into the DutyCycleHelper
    m_channelHelper.AddEvent(duration, txChannel);
 
    // Prepare for the downlink //
 
    // Switch the PHY to the channel so that it will listen here for downlink
    m_phyRx->SetFrequency(txChannel->GetFrequency());
 
    // Instruct the PHY on the right Spreading Factor to listen for during the window
    // create a SetReplyDataRate function?
    uint8_t replyDataRate = GetFirstReceiveWindowDataRate();
    NS_LOG_DEBUG("m_dataRate: " << unsigned(m_dataRate)
                                << ", m_rx1DrOffset: " << unsigned(m_rx1DrOffset)
                                << ", replyDataRate: " << unsigned(replyDataRate) << ".");
 
    m_phyRx->SetSpreadingFactor(GetSfFromDataRate(replyDataRate));
}
 
//  Receiving methods   //
 
void
LorawanMacEndDeviceClassA::Receive(Ptr<Packet> packet)
{
    NS_LOG_FUNCTION(this << packet);
 
    // We add good address and not broadcast for traces
    SatMacTag macTag;
    packet->RemovePacketTag(macTag);
    macTag.SetDestAddress(m_nodeInfo->GetMacAddress());
    packet->AddPacketTag(macTag);
 
    SatAddressE2ETag addressE2ETag;
    packet->RemovePacketTag(addressE2ETag);
    addressE2ETag.SetE2EDestAddress(m_nodeInfo->GetMacAddress());
    packet->AddPacketTag(addressE2ETag);
 
    SatPhy::PacketContainer_t packets;
    packets.push_back(packet);
    RxTraces(packets);
 
    m_phyRx->SwitchToStandby();
 
    // Work on a copy of the packet
    Ptr<Packet> packetCopy = packet->Copy();
 
    SatMacTag mTag;
    packetCopy->RemovePacketTag(mTag);
 
    // Remove the Mac Header to get some information
    LorawanMacHeader mHdr;
    packetCopy->RemoveHeader(mHdr);
 
    NS_LOG_DEBUG("Mac Header: " << mHdr);
 
    // Only keep analyzing the packet if it's downlink
    if (!mHdr.IsUplink())
    {
        NS_LOG_INFO("Found a downlink packet.");
 
        // Remove the Frame Header
        LoraFrameHeader fHdr;
        fHdr.SetAsDownlink();
        packetCopy->RemoveHeader(fHdr);
 
        NS_LOG_DEBUG("Frame Header: " << fHdr);
 
        // Determine whether this packet is for us
        bool messageForUs = (m_address == fHdr.GetAddress());
 
        if (messageForUs)
        {
            NS_LOG_INFO("The message is for us!");
 
            // If it exists, cancel the second receive window event
            // THIS WILL BE GetReceiveWindow()
            Simulator::Cancel(m_secondReceiveWindow);
 
            // Parse the MAC commands
            ParseCommands(fHdr);
 
            // m_device->GetObject<SatLorawanNetDevice> ()->Receive (packetCopy);
 
            // Call the trace source
            m_receivedPacket(packet);
        }
        else
        {
            NS_LOG_DEBUG("The message is intended for another recipient.");
 
            // In this case, we are either receiving in the first receive window
            // and finishing reception inside the second one, or receiving a
            // packet in the second receive window and finding out, after the
            // fact, that the packet is not for us. In either case, if we no
            // longer have any retransmissions left, we declare failure.
            if (m_retxParams.waitingAck && m_secondReceiveWindow.IsExpired())
            {
                if (m_retxParams.retxLeft == 0)
                {
                    uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
                    m_requiredTxCallback(txs,
                                         false,
                                         m_retxParams.firstAttempt,
                                         m_retxParams.packet);
                    NS_LOG_DEBUG("Failure: no more retransmissions left. Used "
                                 << unsigned(txs) << " transmissions.");
 
                    // Reset retransmission parameters
                    resetRetransmissionParameters();
                }
                else // Reschedule
                {
                    this->Send(m_retxParams.packet);
                    NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
                                           << " retransmissions left: rescheduling transmission.");
                }
            }
        }
    }
    else if (m_retxParams.waitingAck && m_secondReceiveWindow.IsExpired())
    {
        NS_LOG_INFO("The packet we are receiving is in uplink.");
        if (m_retxParams.retxLeft > 0)
        {
            this->Send(m_retxParams.packet);
            NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
                                   << " retransmissions left: rescheduling transmission.");
        }
        else
        {
            uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
            m_requiredTxCallback(txs, false, m_retxParams.firstAttempt, m_retxParams.packet);
            NS_LOG_DEBUG("Failure: no more retransmissions left. Used " << unsigned(txs)
                                                                        << " transmissions.");
 
            // Reset retransmission parameters
            resetRetransmissionParameters();
        }
    }
 
    m_phyRx->SwitchToSleep();
}
 
void
LorawanMacEndDeviceClassA::FailedReception(Ptr<const Packet> packet)
{
    NS_LOG_FUNCTION(this << packet);
 
    // Switch to sleep after a failed reception
    m_phyRx->SwitchToSleep();
 
    if (m_secondReceiveWindow.IsExpired() && m_retxParams.waitingAck)
    {
        if (m_retxParams.retxLeft > 0)
        {
            this->Send(m_retxParams.packet);
            NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
                                   << " retransmissions left: rescheduling transmission.");
        }
        else
        {
            uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
            m_requiredTxCallback(txs, false, m_retxParams.firstAttempt, m_retxParams.packet);
            NS_LOG_DEBUG("Failure: no more retransmissions left. Used " << unsigned(txs)
                                                                        << " transmissions.");
 
            // Reset retransmission parameters
            resetRetransmissionParameters();
        }
    }
}
 
void
LorawanMacEndDeviceClassA::TxFinished()
{
    NS_LOG_FUNCTION_NOARGS();
 
    m_phyRx->SwitchToStandby();
 
    // Schedule the opening of the first receive window
    Simulator::Schedule(m_firstWindowDelay,
                        &LorawanMacEndDeviceClassA::OpenFirstReceiveWindow,
                        this);
 
    // Schedule the opening of the second receive window
    m_secondReceiveWindow = Simulator::Schedule(m_secondWindowDelay,
                                                &LorawanMacEndDeviceClassA::OpenSecondReceiveWindow,
                                                this);
 
    // Switch the PHY to sleep
    m_phyRx->SwitchToSleep();
}
 
void
LorawanMacEndDeviceClassA::SetRaModel(SatEnums::RandomAccessModel_t randomAccessModel)
{
    switch (randomAccessModel)
    {
    case SatEnums::RA_MODEL_OFF: {
        m_packetType = SatEnums::PACKET_TYPE_DEDICATED_ACCESS;
        break;
    }
    case SatEnums::RA_MODEL_SLOTTED_ALOHA: {
        m_packetType = SatEnums::PACKET_TYPE_SLOTTED_ALOHA;
        break;
    }
    case SatEnums::RA_MODEL_CRDSA:
    case SatEnums::RA_MODEL_RCS2_SPECIFICATION:
    case SatEnums::RA_MODEL_MARSALA: {
        m_packetType = SatEnums::PACKET_TYPE_CRDSA;
        break;
    }
    case SatEnums::RA_MODEL_ESSA: {
        m_packetType = SatEnums::PACKET_TYPE_ESSA;
        break;
    }
    }
}
 
void
LorawanMacEndDeviceClassA::OpenFirstReceiveWindow(void)
{
    NS_LOG_FUNCTION_NOARGS();
 
    // Set Phy in Standby mode
    m_phyRx->SwitchToStandby();
 
    // Schedule return to sleep after "at least the time required by the end
    // device's radio transceiver to effectively detect a downlink preamble"
    // (LoraWAN specification)
    m_closeFirstWindow = Simulator::Schedule(m_firstWindowDuration,
                                             &LorawanMacEndDeviceClassA::CloseFirstReceiveWindow,
                                             this);
}
 
void
LorawanMacEndDeviceClassA::CloseFirstReceiveWindow(void)
{
    NS_LOG_FUNCTION_NOARGS();
 
    // Check the Phy layer's state:
    // - RX -> We are receiving a preamble.
    // - STANDBY -> Nothing was received.
    // - SLEEP -> We have received a packet.
    // We should never be in TX or SLEEP mode at this point
    switch (m_phyRx->GetState())
    {
    case SatLoraPhyRx::TX:
        NS_ABORT_MSG("PHY was in TX mode when attempting to "
                     << "close a receive window.");
        break;
    case SatLoraPhyRx::RX:
        // PHY is receiving: let it finish. The Receive method will switch it back to SLEEP.
        break;
    case SatLoraPhyRx::SLEEP:
        // PHY has received, and the MAC's Receive already put the device to sleep
        break;
    case SatLoraPhyRx::STANDBY:
        // Turn PHY layer to SLEEP
        m_phyRx->SwitchToSleep();
        break;
    }
}
 
void
LorawanMacEndDeviceClassA::OpenSecondReceiveWindow(void)
{
    NS_LOG_FUNCTION_NOARGS();
 
    // Check for receiver status: if it's locked on a packet, don't open this
    // window at all.
    if (m_phyRx->GetState() == SatLoraPhyRx::RX)
    {
        NS_LOG_INFO("Won't open second receive window since we are in RX mode.");
        return;
    }
 
    // Set Phy in Standby mode
    m_phyRx->SwitchToStandby();
 
    // Switch to appropriate channel and data rate
    NS_LOG_INFO("Using parameters: " << m_secondReceiveWindowFrequency << "Hz, DR"
                                     << unsigned(m_secondReceiveWindowDataRate));
 
    m_phyRx->SetFrequency(m_secondReceiveWindowFrequency);
    m_phyRx->SetSpreadingFactor(GetSfFromDataRate(m_secondReceiveWindowDataRate));
 
    // Schedule return to sleep after "at least the time required by the end
    // device's radio transceiver to effectively detect a downlink preamble"
    // (LoraWAN specification)
    m_closeSecondWindow = Simulator::Schedule(m_secondWindowDuration,
                                              &LorawanMacEndDeviceClassA::CloseSecondReceiveWindow,
                                              this);
}
 
void
LorawanMacEndDeviceClassA::CloseSecondReceiveWindow(void)
{
    NS_LOG_FUNCTION_NOARGS();
 
    // NS_ASSERT (m_phyRx->m_state != SatLoraPhyRx::TX &&
    // m_phyRx->m_state != SatLoraPhyRx::SLEEP);
 
    // Check the Phy layer's state:
    // - RX -> We have received a preamble.
    // - STANDBY -> Nothing was detected.
    switch (m_phyRx->GetState())
    {
    case SatLoraPhyRx::TX:
        break;
    case SatLoraPhyRx::SLEEP:
        break;
    case SatLoraPhyRx::RX:
        // PHY is receiving: let it finish
        NS_LOG_DEBUG("PHY is receiving: Receive will handle the result.");
        return;
    case SatLoraPhyRx::STANDBY:
        // Turn PHY layer to sleep
        m_phyRx->SwitchToSleep();
        break;
    }
 
    if (m_retxParams.waitingAck)
    {
        NS_LOG_DEBUG("No reception initiated by PHY: rescheduling transmission.");
        if (m_retxParams.retxLeft > 0)
        {
            NS_LOG_INFO("We have " << unsigned(m_retxParams.retxLeft)
                                   << " retransmissions left: rescheduling transmission.");
            this->Send(m_retxParams.packet);
        }
 
        else if (m_retxParams.retxLeft == 0 && m_phyRx->GetState() != SatLoraPhyRx::RX)
        {
            uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
            m_requiredTxCallback(txs, false, m_retxParams.firstAttempt, m_retxParams.packet);
            NS_LOG_DEBUG("Failure: no more retransmissions left. Used " << unsigned(txs)
                                                                        << " transmissions.");
 
            // Reset retransmission parameters
            resetRetransmissionParameters();
        }
 
        else
        {
            NS_ABORT_MSG("The number of retransmissions left is negative ! ");
        }
    }
    else
    {
        uint8_t txs = m_maxNumbTx - (m_retxParams.retxLeft);
        m_requiredTxCallback(txs, true, m_retxParams.firstAttempt, m_retxParams.packet);
        NS_LOG_INFO(
            "We have " << unsigned(m_retxParams.retxLeft)
                       << " transmissions left. We were not transmitting confirmed messages.");
 
        // Reset retransmission parameters
        resetRetransmissionParameters();
    }
}
 
// Getters and Setters //
 
Time
LorawanMacEndDeviceClassA::GetNextClassTransmissionDelay(Time waitingTime)
{
    NS_LOG_FUNCTION_NOARGS();
 
    // This is a new packet from APP; it can not be sent until the end of the
    // second receive window (if the second recieve window has not closed yet)
    if (!m_retxParams.waitingAck)
    {
        if (!m_closeFirstWindow.IsExpired() || !m_closeSecondWindow.IsExpired() ||
            !m_secondReceiveWindow.IsExpired())
        {
            NS_LOG_WARN("Attempting to send when there are receive windows:"
                        << " Transmission postponed.");
            // Compute the duration of a single symbol for the second receive window DR
            double tSym = pow(2, GetSfFromDataRate(GetSecondReceiveWindowDataRate())) /
                          GetBandwidthFromDataRate(GetSecondReceiveWindowDataRate());
            // Compute the closing time of the second receive window
            Time endSecondRxWindow = Time(m_secondReceiveWindow.GetTs()) +
                                     Seconds(m_receiveWindowDurationInSymbols * tSym);
 
            NS_LOG_DEBUG("Duration until endSecondRxWindow for new transmission:"
                         << (endSecondRxWindow - Simulator::Now()).GetSeconds());
            waitingTime = std::max(waitingTime, endSecondRxWindow - Simulator::Now());
        }
    }
    // This is a retransmitted packet, it can not be sent until the end of
    // ACK_TIMEOUT (this timer starts when the second receive window was open)
    else
    {
        double ack_timeout = m_uniformRV->GetValue(1, 3);
        // Compute the duration until ACK_TIMEOUT (It may be a negative number, but it doesn't
        // matter.)
        Time retransmitWaitingTime =
            Time(m_secondReceiveWindow.GetTs()) - Simulator::Now() + Seconds(ack_timeout);
 
        NS_LOG_DEBUG("ack_timeout:" << ack_timeout << " retransmitWaitingTime:"
                                    << retransmitWaitingTime.GetSeconds());
        waitingTime = std::max(waitingTime, retransmitWaitingTime);
    }
 
    return waitingTime;
}
 
uint8_t
LorawanMacEndDeviceClassA::GetFirstReceiveWindowDataRate(void)
{
    return m_replyDataRateMatrix.at(m_dataRate).at(m_rx1DrOffset);
}
 
void
LorawanMacEndDeviceClassA::SetSecondReceiveWindowDataRate(uint8_t dataRate)
{
    m_secondReceiveWindowDataRate = dataRate;
}
 
uint8_t
LorawanMacEndDeviceClassA::GetSecondReceiveWindowDataRate(void)
{
    return m_secondReceiveWindowDataRate;
}
 
void
LorawanMacEndDeviceClassA::SetSecondReceiveWindowFrequency(double frequencyMHz)
{
    m_secondReceiveWindowFrequency = frequencyMHz;
}
 
double
LorawanMacEndDeviceClassA::GetSecondReceiveWindowFrequency(void)
{
    return m_secondReceiveWindowFrequency;
}
 
// MAC command methods //
 
void
LorawanMacEndDeviceClassA::OnRxClassParamSetupReq(Ptr<RxParamSetupReq> rxParamSetupReq)
{
    NS_LOG_FUNCTION(this << rxParamSetupReq);
 
    bool offsetOk = true;
    bool dataRateOk = true;
 
    uint8_t rx1DrOffset = rxParamSetupReq->GetRx1DrOffset();
    uint8_t rx2DataRate = rxParamSetupReq->GetRx2DataRate();
    double frequency = rxParamSetupReq->GetFrequency();
 
    NS_LOG_FUNCTION(this << unsigned(rx1DrOffset) << unsigned(rx2DataRate) << frequency);
 
    // Check that the desired offset is valid
    if (!(0 <= rx1DrOffset && rx1DrOffset <= 5))
    {
        offsetOk = false;
    }
 
    // Check that the desired data rate is valid
    if (GetSfFromDataRate(rx2DataRate) == 0 || GetBandwidthFromDataRate(rx2DataRate) == 0)
    {
        dataRateOk = false;
    }
 
    // For now, don't check for validity of frequency
    m_secondReceiveWindowDataRate = rx2DataRate;
    m_rx1DrOffset = rx1DrOffset;
    m_secondReceiveWindowFrequency = frequency;
 
    // Craft a RxParamSetupAns as response
    NS_LOG_INFO("Adding RxParamSetupAns reply");
    m_macCommandList.push_back(CreateObject<RxParamSetupAns>(offsetOk, dataRateOk, true));
}
 
} /* namespace ns3 */