satellite-ut-mac.cc

Go to the documentation of this file.

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014 Magister Solutions Ltd
 * Copyright (c) 2018 CNES
 *
 * 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: Sami Rantanen <sami.rantanen@magister.fi>
 * Author: Mathias Ettinger <mettinger@toulouse.viveris.fr>
 */
 
#include "satellite-ut-mac.h"
 
#include "satellite-beam-scheduler.h"
#include "satellite-const-variables.h"
#include "satellite-control-message.h"
#include "satellite-crdsa-replica-tag.h"
#include "satellite-encap-pdu-status-tag.h"
#include "satellite-frame-conf.h"
#include "satellite-id-mapper.h"
#include "satellite-log.h"
#include "satellite-node-info.h"
#include "satellite-rtn-link-time.h"
#include "satellite-superframe-sequence.h"
#include "satellite-tbtp-container.h"
#include "satellite-topology.h"
#include "satellite-utils.h"
#include "satellite-wave-form-conf.h"
 
#include "ns3/boolean.h"
#include "ns3/log.h"
#include "ns3/mac48-address.h"
#include "ns3/packet.h"
#include "ns3/pointer.h"
#include "ns3/random-variable-stream.h"
#include "ns3/simulator.h"
#include "ns3/singleton.h"
 
#include <iostream>
#include <map>
#include <set>
#include <sstream>
#include <utility>
#include <vector>
 
NS_LOG_COMPONENT_DEFINE("SatUtMac");
 
namespace ns3
{
 
NS_OBJECT_ENSURE_REGISTERED(SatUtMac);
 
TypeId
SatUtMac::GetTypeId(void)
{
    static TypeId tid =
        TypeId("ns3::SatUtMac")
            .SetParent<SatMac>()
            .AddConstructor<SatUtMac>()
            .AddAttribute("MaxHandoverMessages",
                          "Max amount of handover messages to send without a handover response "
                          "before loging off",
                          UintegerValue(20),
                          MakeUintegerAccessor(&SatUtMac::m_maxHandoverMessagesSent),
                          MakeUintegerChecker<uint32_t>())
            .AddAttribute("SuperframeSequence",
                          "Superframe sequence containing information of superframes.",
                          PointerValue(),
                          MakePointerAccessor(&SatUtMac::m_superframeSeq),
                          MakePointerChecker<SatSuperframeSeq>())
            .AddAttribute("GuardTime",
                          "Guard time in return link",
                          TimeValue(MicroSeconds(1)),
                          MakeTimeAccessor(&SatUtMac::m_guardTime),
                          MakeTimeChecker())
            .AddAttribute("Scheduler",
                          "UT scheduler used by this Sat UT MAC.",
                          PointerValue(),
                          MakePointerAccessor(&SatUtMac::m_utScheduler),
                          MakePointerChecker<SatUtScheduler>())
            .AddAttribute("WindowInitLogon",
                          "The initial window for logon waiting time before transmission.",
                          TimeValue(Seconds(20)),
                          MakeTimeAccessor(&SatUtMac::m_windowInitLogon),
                          MakeTimeChecker())
            .AddAttribute("MaxWaitingTimeLogonResponse",
                          "Timeout for waiting for a response for a logon message.",
                          TimeValue(Seconds(1)),
                          MakeTimeAccessor(&SatUtMac::m_maxWaitingTimeLogonResponse),
                          MakeTimeChecker())
            .AddAttribute("ClockDrift",
                          "Clock drift (number of ticks per second).",
                          IntegerValue(0),
                          MakeIntegerAccessor(&SatUtMac::m_clockDrift),
                          MakeIntegerChecker<int32_t>())
            .AddTraceSource("DaResourcesTrace",
                            "Assigned dedicated access resources in return link to this UT.",
                            MakeTraceSourceAccessor(&SatUtMac::m_tbtpResourcesTrace),
                            "ns3::SatUtMac::TbtpResourcesTraceCallback");
    return tid;
}
 
SatUtMac::SatUtMac()
    : SatMac(),
      m_satId(0),
      m_beamId(),
      m_superframeSeq(),
      m_timingAdvanceCb(),
      m_randomAccess(nullptr),
      m_guardTime(MicroSeconds(1)),
      m_raChannel(0),
      m_logonChannel(0),
      m_loggedOn(true),
      m_useLogon(false),
      m_sendLogonTries(0),
      m_windowInitLogon(Seconds(20)),
      m_maxWaitingTimeLogonResponse(Seconds(1)),
      m_waitingTimeLogonRng(CreateObject<UniformRandomVariable>()),
      m_nextLogonTransmissionPossible(Seconds(0)),
      m_crdsaUniquePacketId(1),
      m_crdsaOnlyForControl(false),
      m_nextPacketTime(Now()),
      m_isRandomAccessScheduled(false),
      m_timuInfo(0),
      m_rcstState(SatUtMacState()),
      m_lastNcrDateReceived(Seconds(0)),
      m_ncr(0),
      m_deltaNcr(0),
      m_clockDrift(0),
      m_handoverState(NO_HANDOVER),
      m_handoverMessagesCount(0),
      m_maxHandoverMessagesSent(20),
      m_firstTransmittableSuperframeId(0),
      m_handoverCallback(),
      m_gatewayUpdateCallback(),
      m_txCheckCallback(),
      m_sliceSubscriptionCallback(),
      m_sendLogonCallback(),
      m_updateGwAddressCallback()
{
    NS_LOG_FUNCTION(this);
 
    // default constructor should not be used
    NS_FATAL_ERROR("SatUtMac::SatUtMac - Constructor not in use");
}
 
SatUtMac::SatUtMac(Ptr<Node> node,
                   uint32_t satId,
                   uint32_t beamId,
                   Ptr<SatSuperframeSeq> seq,
                   bool crdsaOnlyForControl)
    : SatMac(satId, beamId),
      m_node(node),
      m_satId(satId),
      m_beamId(beamId),
      m_superframeSeq(seq),
      m_timingAdvanceCb(),
      m_guardTime(MicroSeconds(1)),
      m_raChannel(0),
      m_logonChannel(0),
      m_loggedOn(true),
      m_useLogon(false),
      m_sendLogonTries(0),
      m_windowInitLogon(Seconds(20)),
      m_maxWaitingTimeLogonResponse(Seconds(1)),
      m_waitingTimeLogonRng(CreateObject<UniformRandomVariable>()),
      m_nextLogonTransmissionPossible(Seconds(0)),
      m_crdsaUniquePacketId(1),
      m_crdsaOnlyForControl(crdsaOnlyForControl),
      m_nextPacketTime(Now()),
      m_isRandomAccessScheduled(false),
      m_timuInfo(0),
      m_rcstState(SatUtMacState()),
      m_lastNcrDateReceived(Seconds(0)),
      m_ncr(0),
      m_deltaNcr(0),
      m_clockDrift(0),
      m_handoverState(NO_HANDOVER),
      m_handoverMessagesCount(0),
      m_maxHandoverMessagesSent(20),
      m_firstTransmittableSuperframeId(0),
      m_handoverCallback(),
      m_gatewayUpdateCallback(),
      m_txCheckCallback(),
      m_sliceSubscriptionCallback(),
      m_sendLogonCallback(),
      m_updateGwAddressCallback()
{
    NS_LOG_FUNCTION(this);
 
    m_uniformRandomVariable = CreateObject<UniformRandomVariable>();
    m_tbtpContainer = CreateObject<SatTbtpContainer>(m_superframeSeq);
}
 
SatUtMac::~SatUtMac()
{
    NS_LOG_FUNCTION(this);
 
    m_randomAccess = nullptr;
    m_tbtpContainer = nullptr;
    m_timuInfo = nullptr;
}
 
void
SatUtMac::DoDispose(void)
{
    NS_LOG_FUNCTION(this);
 
    m_timingAdvanceCb.Nullify();
    m_handoverCallback.Nullify();
    m_gatewayUpdateCallback.Nullify();
    m_txCheckCallback.Nullify();
    m_sliceSubscriptionCallback.Nullify();
    m_sendLogonCallback.Nullify();
    m_updateGwAddressCallback.Nullify();
    m_tbtpContainer->DoDispose();
    m_utScheduler->DoDispose();
    m_utScheduler = nullptr;
 
    SatMac::DoDispose();
}
 
void
SatUtMac::SetHandoverCallback(SatUtMac::HandoverCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
    m_handoverCallback = cb;
}
 
void
SatUtMac::SetGatewayUpdateCallback(SatUtMac::GatewayUpdateCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
    m_gatewayUpdateCallback = cb;
}
 
void
SatUtMac::SetUpdateAddressAndIdentifierCallback(SatUtMac::UpdateAddressAndIdentifierCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
    m_updateAddressAndIdentifierCallback = cb;
}
 
void
SatUtMac::SetTxCheckCallback(SatUtMac::TxCheckCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
 
    m_txCheckCallback = cb;
}
 
void
SatUtMac::SetSliceSubscriptionCallback(SatUtMac::SliceSubscriptionCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
 
    m_sliceSubscriptionCallback = cb;
}
 
void
SatUtMac::SetSendLogonCallback(SatUtMac::SendLogonCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
 
    m_sendLogonCallback = cb;
}
 
void
SatUtMac::SetUpdateGwAddressCallback(SatUtMac::UpdateGwAddressCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
 
    m_updateGwAddressCallback = cb;
}
 
void
SatUtMac::SetSatelliteAddress(Address satelliteAddress)
{
    m_satelliteAddress = satelliteAddress;
    m_isRegenerative = true;
}
 
Mac48Address
SatUtMac::GetGwAddress()
{
    NS_LOG_FUNCTION(this);
 
    return m_gwAddress;
}
 
void
SatUtMac::SetGwAddress(Mac48Address gwAddress)
{
    NS_LOG_FUNCTION(this << gwAddress);
 
    m_gatewayUpdateCallback(gwAddress);
    m_gwAddress = gwAddress;
}
 
void
SatUtMac::SetNodeInfo(Ptr<SatNodeInfo> nodeInfo)
{
    NS_LOG_FUNCTION(this << nodeInfo);
 
    m_tbtpContainer->SetMacAddress(nodeInfo->GetMacAddress());
    m_utScheduler->SetNodeInfo(nodeInfo);
    SatMac::SetNodeInfo(nodeInfo);
}
 
void
SatUtMac::LogOff()
{
    NS_LOG_FUNCTION(this);
    m_loggedOn = false;
    m_raChannel = m_logonChannel;
    m_rcstState.SwitchToOffStandby();
}
 
void
SatUtMac::SetLogonChannel(uint32_t channelId)
{
    NS_LOG_FUNCTION(this);
    m_logonChannel = channelId;
    m_useLogon = true;
}
 
void
SatUtMac::SetRaChannel(uint32_t raChannel)
{
    NS_LOG_FUNCTION(this << raChannel);
 
    m_raChannel = raChannel;
}
 
uint32_t
SatUtMac::GetRaChannel() const
{
    NS_LOG_FUNCTION(this);
 
    return m_raChannel;
}
 
void
SatUtMac::SetRandomAccess(Ptr<SatRandomAccess> randomAccess)
{
    NS_LOG_FUNCTION(this);
 
    m_randomAccess = randomAccess;
    m_randomAccess->SetIsDamaAvailableCallback(
        MakeCallback(&SatTbtpContainer::HasScheduledTimeSlots, m_tbtpContainer));
}
 
bool
SatUtMac::ControlMsgTransmissionPossible() const
{
    NS_LOG_FUNCTION(this);
 
    bool da = m_tbtpContainer->HasScheduledTimeSlots();
    bool ra = (m_randomAccess != nullptr);
    if (m_useLogon)
    {
        ra = ra && (m_raChannel != m_logonChannel);
    }
    return da || ra;
}
 
bool
SatUtMac::LogonMsgTransmissionPossible() const
{
    NS_LOG_FUNCTION(this);
 
    bool stateCorrect = (m_rcstState.GetState() == SatUtMacState::RcstState_t::READY_FOR_LOGON);
    bool ncrReceived = !m_rcstState.IsNcrTimeout();
 
    return m_useLogon && stateCorrect && ncrReceived;
}
 
void
SatUtMac::SetTimingAdvanceCallback(SatUtMac::TimingAdvanceCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
 
    m_timingAdvanceCb = cb;

    Time nextSuperFrameTxTime = GetNextSuperFrameTxTime(SatConstVariables::SUPERFRAME_SEQUENCE);
 
    if (Now() >= nextSuperFrameTxTime)
    {
        NS_FATAL_ERROR("Scheduling next superframe start time to the past!");
    }
 
    Time schedulingDelay = nextSuperFrameTxTime - Now();
 
    Simulator::Schedule(GetRealSendingTime(schedulingDelay), &SatUtMac::DoFrameStart, this);
}
 
void
SatUtMac::SetAssignedDaResourcesCallback(SatUtMac::AssignedDaResourcesCallback cb)
{
    NS_LOG_FUNCTION(this << &cb);
 
    m_assignedDaResourcesCallback = cb;
}
 
Time
SatUtMac::GetNextSuperFrameTxTime(uint8_t superFrameSeqId) const
{
    NS_LOG_FUNCTION(this << (uint32_t)superFrameSeqId);
 
    Time timingAdvance = m_timingAdvanceCb();
    Time txTime =
        Singleton<SatRtnLinkTime>::Get()->GetNextSuperFrameTxTime(superFrameSeqId, timingAdvance);
    return txTime;
}
 
Time
SatUtMac::GetCurrentSuperFrameStartTime(uint8_t superFrameSeqId) const
{
    NS_LOG_FUNCTION(this << (uint32_t)superFrameSeqId);
 
    Time timingAdvance = m_timingAdvanceCb();
    Time txTime = Singleton<SatRtnLinkTime>::Get()->GetCurrentSuperFrameTxTime(superFrameSeqId,
                                                                               timingAdvance);
    return txTime;
}
 
uint32_t
SatUtMac::GetCurrentSuperFrameId(uint8_t superFrameSeqId) const
{
    NS_LOG_FUNCTION(this << (uint32_t)superFrameSeqId);
 
    return Singleton<SatRtnLinkTime>::Get()->GetCurrentSuperFrameCount(superFrameSeqId,
                                                                       m_timingAdvanceCb());
}
 
void
SatUtMac::ScheduleTimeSlots(Ptr<SatTbtpMessage> tbtp)
{
    NS_LOG_FUNCTION(this << tbtp);
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " received TBTP "
                       << tbtp->GetSuperframeCounter());


    if (m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE)
            ->GetConfigType() == SatSuperframeConf::CONFIG_TYPE_4)
    {
        return;
    }
 
    Time timingAdvance = m_timingAdvanceCb();
    Time txTime =
        Singleton<SatRtnLinkTime>::Get()->GetSuperFrameTxTime(tbtp->GetSuperframeSeqId(),
                                                              tbtp->GetSuperframeCounter(),
                                                              timingAdvance);
 
    // The delay compared to Now when to start the transmission of this superframe
    Time startDelay = txTime - Simulator::Now();
 
    // Add TBTP to a specific container
    m_tbtpContainer->Add(txTime, tbtp);
 
    // if the calculated start time of the superframe is already in the past
    if (txTime < Simulator::Now())
    {
        NS_FATAL_ERROR("UT: " << m_nodeInfo->GetMacAddress() << " received TBTP "
                              << tbtp->GetSuperframeCounter()
                              << ", which should have been sent already in the past");
    }
 
    NS_LOG_INFO("Time to start sending the superframe for this UT: " << txTime.GetSeconds());
    NS_LOG_INFO("Waiting delay before the superframe start: " << startDelay.GetSeconds());
 
    SatTbtpMessage::DaTimeSlotInfoItem_t info = tbtp->GetDaTimeslots(m_nodeInfo->GetMacAddress());
 
    // Counters for allocated TBTP resources
    uint32_t payloadSumInSuperFrame = 0;
    uint32_t payloadSumPerRcIndex[SatEnums::NUM_FIDS] = {};
 
    if (!info.second.empty())
    {
        NS_LOG_INFO("TBTP contains " << info.second.size()
                                     << " timeslots for UT: " << m_nodeInfo->GetMacAddress());
 
        uint8_t frameId = info.first;
 
        // schedule time slots
        for (SatTbtpMessage::DaTimeSlotConfContainer_t::iterator it = info.second.begin();
             it != info.second.end();
             it++)
        {
            Ptr<SatSuperframeConf> superframeConf =
                m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE);
            Ptr<SatFrameConf> frameConf = superframeConf->GetFrameConf(frameId);
            Ptr<SatTimeSlotConf> timeSlotConf = *it;
 
            // Start time
            Time slotDelay = startDelay + timeSlotConf->GetStartTime();
            NS_LOG_INFO("Slot start delay: " << slotDelay.GetSeconds());
 
            // Duration
            Ptr<SatWaveform> wf =
                m_superframeSeq->GetWaveformConf()->GetWaveform(timeSlotConf->GetWaveFormId());
            Time duration = wf->GetBurstDuration(frameConf->GetBtuConf()->GetSymbolRateInBauds());
 
            bool drop = false;
            if (timeSlotConf->GetSlotType() == SatTimeSlotConf::SLOT_TYPE_C)
            {
                wf = m_superframeSeq->GetWaveformConf()->GetWaveform(2);
                duration = wf->GetBurstDuration(frameConf->GetBtuConf()->GetSymbolRateInBauds());
                if (m_useLogon && m_rcstState.GetState() != SatUtMacState::RcstState_t::TDMA_SYNC &&
                    m_rcstState.GetState() != SatUtMacState::RcstState_t::READY_FOR_TDMA_SYNC)
                {
                    drop = true;
                }
            }
 
            // Carrier
            uint32_t carrierId =
                m_superframeSeq->GetCarrierId(0, frameId, timeSlotConf->GetCarrierId());
 
            if (!drop)
            {
                // Schedule individual time slot
                ScheduleDaTxOpportunity(slotDelay, duration, wf, timeSlotConf, carrierId);
 
                payloadSumInSuperFrame += wf->GetPayloadInBytes();
                payloadSumPerRcIndex[timeSlotConf->GetRcIndex()] += wf->GetPayloadInBytes();
            }
        }
    }
 
    // Assigned TBTP resources
    m_tbtpResourcesTrace(payloadSumInSuperFrame);
 
    // Update the allocated TBTP resources for each RC index
    for (uint32_t i = 0; i < SatEnums::NUM_FIDS; ++i)
    {
        m_assignedDaResourcesCallback(i, payloadSumPerRcIndex[i]);
    }
}
 
void
SatUtMac::ScheduleDaTxOpportunity(Time transmitDelay,
                                  Time duration,
                                  Ptr<SatWaveform> wf,
                                  Ptr<SatTimeSlotConf> tsConf,
                                  uint32_t carrierId)
{
    NS_LOG_FUNCTION(this << transmitDelay.GetSeconds() << duration.GetSeconds()
                         << wf->GetPayloadInBytes() << (uint32_t)(tsConf->GetRcIndex())
                         << carrierId);
    NS_LOG_INFO("After delay: " << transmitDelay.GetSeconds() << " duration: "
                                << duration.GetSeconds() << ", payload: " << wf->GetPayloadInBytes()
                                << ", rcIndex: " << (uint32_t)(tsConf->GetRcIndex())
                                << ", carrier: " << carrierId);
 
    transmitDelay = GetRealSendingTime(transmitDelay);
 
    if (transmitDelay >= Seconds(0))
    {
        Simulator::Schedule(transmitDelay,
                            &SatUtMac::DoTransmit,
                            this,
                            duration,
                            carrierId,
                            wf,
                            tsConf,
                            SatUtScheduler::LOOSE);
    }
}
 
void
SatUtMac::DoTransmit(Time duration,
                     uint32_t carrierId,
                     Ptr<SatWaveform> wf,
                     Ptr<SatTimeSlotConf> tsConf,
                     SatUtScheduler::SatCompliancePolicy_t policy)
{
    NS_LOG_FUNCTION(this << duration.GetSeconds() << wf->GetPayloadInBytes() << carrierId
                         << (uint32_t)(tsConf->GetRcIndex()));
 
    if (!m_txCheckCallback())
    {
        NS_LOG_INFO("Tx is unavailable");
        m_rcstState.SwitchToHoldStandby();
        return;
    }
 
    if ((m_rcstState.GetState() != SatUtMacState::RcstState_t::TDMA_SYNC) &&
        (tsConf->GetSlotType() != SatTimeSlotConf::SLOT_TYPE_C) && m_useLogon)
    {
        return;
    }
 
    SatPhy::PacketContainer_t packets =
        FetchPackets(wf->GetPayloadInBytes(), tsConf->GetSlotType(), tsConf->GetRcIndex(), policy);
 
    if (wf == m_superframeSeq->GetWaveformConf()->GetWaveform(2))
    {
        if (packets.size() == 0)
        {
            Ptr<Packet> p = Create<Packet>(wf->GetPayloadInBytes());
 
            // Mark the PDU with FULL_PDU tag
            SatEncapPduStatusTag tag;
            tag.SetStatus(SatEncapPduStatusTag::FULL_PDU);
            p->AddPacketTag(tag);
 
            // Add MAC tag to identify the packet in lower layers
            SatMacTag mTag;
            if (m_returnLinkRegenerationMode == SatEnums::REGENERATION_LINK ||
                m_returnLinkRegenerationMode == SatEnums::REGENERATION_NETWORK)
            {
                mTag.SetDestAddress(Mac48Address::ConvertFrom(m_satelliteAddress));
            }
            else
            {
                mTag.SetDestAddress(m_gwAddress);
            }
            mTag.SetSourceAddress(m_nodeInfo->GetMacAddress());
            p->AddPacketTag(mTag);
 
            // Add MAC tag to identify the packet in lower layers
            SatAddressE2ETag addressE2ETag;
            addressE2ETag.SetE2EDestAddress(m_gwAddress);
            addressE2ETag.SetE2ESourceAddress(m_nodeInfo->GetMacAddress());
            p->AddPacketTag(addressE2ETag);
 
            packets.push_back(p);
        }
    }
 
    NS_LOG_INFO("DA Tx opportunity for UT: "
                << m_nodeInfo->GetMacAddress() << " duration: " << duration.GetSeconds()
                << ", payload: " << wf->GetPayloadInBytes() << ", carrier: " << carrierId
                << ", RC index: " << (uint32_t)(tsConf->GetRcIndex()));
 
    SatSignalParameters::txInfo_s txInfo;
    txInfo.packetType = SatEnums::PACKET_TYPE_DEDICATED_ACCESS;
    txInfo.modCod = wf->GetModCod();
    txInfo.fecBlockSizeInBytes = wf->GetPayloadInBytes();
    txInfo.frameType = SatEnums::UNDEFINED_FRAME;
    txInfo.waveformId = wf->GetWaveformId();
 
    if (txInfo.waveformId == 2 && tsConf->GetSlotType() != SatTimeSlotConf::SLOT_TYPE_C)
    {
        NS_FATAL_ERROR("WF02 should only be used for control bursts");
    }
 
    TransmitPackets(packets, duration, carrierId, txInfo);
}
 
void
SatUtMac::DoSlottedAlohaTransmit(Time duration,
                                 Ptr<SatWaveform> waveform,
                                 uint32_t carrierId,
                                 uint8_t rcIndex,
                                 SatUtScheduler::SatCompliancePolicy_t policy)
{
    NS_LOG_FUNCTION(this << duration.GetSeconds() << waveform->GetPayloadInBytes() << carrierId
                         << (uint32_t)(rcIndex));
    NS_LOG_INFO("Tx opportunity for UT: "
                << m_nodeInfo->GetMacAddress() << " duration: " << duration.GetSeconds()
                << ", payload: " << waveform->GetPayloadInBytes() << ", carrier: " << carrierId
                << ", RC index: " << (uint32_t)(rcIndex));
 
    SatPhy::PacketContainer_t packets;

    uint32_t payloadBytes = waveform->GetPayloadInBytes();

    payloadBytes -= m_randomAccess->GetSlottedAlohaSignalingOverheadInBytes();
 
    if (payloadBytes < 1)
    {
        NS_FATAL_ERROR(
            "SatUtMac::DoSlottedAlohaTransmit - Not enough capacity in Slotted ALOHA payload");
    }
 
    ExtractPacketsToSchedule(packets,
                             payloadBytes,
                             SatTimeSlotConf::SLOT_TYPE_C,
                             rcIndex,
                             policy,
                             true);
 
    if (!packets.empty())
    {
        NS_LOG_INFO("Number of packets sent in a slotted ALOHA slot: " << packets.size());
 
        for (SatPhy::PacketContainer_t::const_iterator it = packets.begin(); it != packets.end();
             ++it)
        {
            // Add packet trace entry:
            m_packetTrace(Simulator::Now(),
                          SatEnums::PACKET_SENT,
                          m_nodeInfo->GetNodeType(),
                          m_nodeInfo->GetNodeId(),
                          m_nodeInfo->GetMacAddress(),
                          SatEnums::LL_MAC,
                          SatEnums::LD_RETURN,
                          SatUtils::GetPacketInfo(*it));
        }
 
        SatSignalParameters::txInfo_s txInfo;
        txInfo.packetType = SatEnums::PACKET_TYPE_SLOTTED_ALOHA;
        txInfo.modCod = waveform->GetModCod();
        txInfo.fecBlockSizeInBytes = waveform->GetPayloadInBytes();
        txInfo.frameType = SatEnums::UNDEFINED_FRAME;
        txInfo.waveformId = waveform->GetWaveformId();
 
        TransmitPackets(packets, duration, carrierId, txInfo);
    }
}
 
void
SatUtMac::DoEssaTransmit(Time duration,
                         Ptr<SatWaveform> waveform,
                         uint32_t carrierId,
                         uint8_t rcIndex,
                         SatUtScheduler::SatCompliancePolicy_t policy)
{
    NS_LOG_FUNCTION(this << duration.GetSeconds() << waveform->GetPayloadInBytes() << carrierId
                         << (uint32_t)(rcIndex));
    NS_LOG_INFO("SatUtMac::DoEssaTransmit - Tx opportunity for UT: "
                << m_nodeInfo->GetMacAddress() << " at time: " << Simulator::Now().GetSeconds()
                << " duration: " << duration.GetSeconds()
                << ", payload: " << waveform->GetPayloadInBytes() << ", carrier: " << carrierId
                << ", RC index: " << (uint32_t)(rcIndex));

    uint32_t payloadBytes = waveform->GetPayloadInBytes();

    SatPhy::PacketContainer_t packets;
    m_utScheduler->DoScheduling(packets,
                                payloadBytes,
                                SatTimeSlotConf::SLOT_TYPE_TRC,
                                rcIndex,
                                policy);
 
    if (!packets.empty())
    {
        NS_LOG_INFO("Number of packets sent in a ESSA frame: " << packets.size());
 
        for (SatPhy::PacketContainer_t::const_iterator it = packets.begin(); it != packets.end();
             ++it)
        {
            // Add packet trace entry:
            m_packetTrace(Simulator::Now(),
                          SatEnums::PACKET_SENT,
                          m_nodeInfo->GetNodeType(),
                          m_nodeInfo->GetNodeId(),
                          m_nodeInfo->GetMacAddress(),
                          SatEnums::LL_MAC,
                          SatEnums::LD_RETURN,
                          SatUtils::GetPacketInfo(*it));
        }

        SatSignalParameters::txInfo_s txInfo;
        txInfo.packetType = SatEnums::PACKET_TYPE_ESSA;
        txInfo.modCod = waveform->GetModCod();
        txInfo.fecBlockSizeInBytes = waveform->GetPayloadInBytes();
        txInfo.frameType = SatEnums::UNDEFINED_FRAME;
        txInfo.waveformId = waveform->GetWaveformId();
        txInfo.crdsaUniquePacketId =
            m_crdsaUniquePacketId; // reuse the crdsaUniquePacketId to identify ESSA frames
 
        TransmitPackets(packets, duration, carrierId, txInfo);
        m_crdsaUniquePacketId++;
        m_nextPacketTime =
            Now() + duration; // TODO: this doesn't take into account the guard bands !!
        duration = GetRealSendingTime(duration);
        if (duration >= Seconds(0))
        {
            Simulator::Schedule(duration,
                                &SatUtMac::DoRandomAccess,
                                this,
                                SatEnums::RA_TRIGGER_TYPE_ESSA);
        }
        m_isRandomAccessScheduled = true;
    }
    else
    {
        m_isRandomAccessScheduled = false;
    }
}
 
SatPhy::PacketContainer_t
SatUtMac::FetchPackets(uint32_t payloadBytes,
                       SatTimeSlotConf::SatTimeSlotType_t type,
                       uint8_t rcIndex,
                       SatUtScheduler::SatCompliancePolicy_t policy)
{
    NS_LOG_FUNCTION(this << payloadBytes << (uint32_t)(rcIndex));

    SatPhy::PacketContainer_t packets;
 
    if (payloadBytes <= 0)
    {
        NS_FATAL_ERROR("SatUtMac::FetchPackets - unvalid slot payload: " << payloadBytes);
    }
 
    ExtractPacketsToSchedule(packets, payloadBytes, type, rcIndex, policy, false);
 
    // A valid packet received
    if (!packets.empty())
    {
        NS_LOG_INFO("Number of packets: " << packets.size());
 
        for (SatPhy::PacketContainer_t::const_iterator it = packets.begin(); it != packets.end();
             ++it)
        {
            // Add packet trace entry:
            m_packetTrace(Simulator::Now(),
                          SatEnums::PACKET_SENT,
                          m_nodeInfo->GetNodeType(),
                          m_nodeInfo->GetNodeId(),
                          m_nodeInfo->GetMacAddress(),
                          SatEnums::LL_MAC,
                          SatEnums::LD_RETURN,
                          SatUtils::GetPacketInfo(*it));
        }
    }
 
    NS_LOG_INFO("The Frame PDU holds " << packets.size() << " RLE PDUs");
 
    return packets;
}
 
void
SatUtMac::TransmitPackets(SatPhy::PacketContainer_t packets,
                          Time duration,
                          uint32_t carrierId,
                          SatSignalParameters::txInfo_s txInfo)
{
    NS_LOG_FUNCTION(this << packets.size() << duration.GetSeconds() << carrierId);
 
    if (m_rcstState.GetState() == SatUtMacState::RcstState_t::HOLD_STANDBY)
    {
        m_rcstState.SwitchToOffStandby();
    }
 
    if (m_rcstState.GetState() == SatUtMacState::RcstState_t::READY_FOR_TDMA_SYNC)
    {
        m_rcstState.SwitchToTdmaSync();
    }
 
    // If there are packets to send
    if (!packets.empty())
    {
        NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << ", transmitting " << packets.size()
                           << " packets, duration: " << duration.GetSeconds()
                           << ", carrier: " << carrierId);
 
        // Decrease a guard time from time slot duration.
        Time durationWithoutGuardPeriod(duration - m_guardTime);
        NS_LOG_INFO("Duration: " << duration.GetSeconds() << " duration with guard period: "
                                 << durationWithoutGuardPeriod.GetSeconds());
        NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " send packet");
 
        SendPacket(packets, carrierId, durationWithoutGuardPeriod, txInfo);
    }
}
 
void
SatUtMac::ReceiveQueueEvent(SatQueue::QueueEvent_t event, uint8_t rcIndex)
{
    NS_LOG_FUNCTION(this << event << (uint32_t)rcIndex);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " Queue: " << (uint32_t)rcIndex);
 
    // Check only the queue events from the control queue
    if (rcIndex == SatEnums::CONTROL_FID)
    {
        if (event == SatQueue::FIRST_BUFFERED_PKT || event == SatQueue::BUFFERED_PKT)
        {
            NS_LOG_INFO("Buffered packet event received");
 
            if (m_randomAccess != nullptr)
            {
                NS_LOG_INFO("Doing Slotted ALOHA");
 
                DoRandomAccess(SatEnums::RA_TRIGGER_TYPE_SLOTTED_ALOHA);
            }
        }
    }
}
 
void
SatUtMac::ReceiveQueueEventEssa(SatQueue::QueueEvent_t event, uint8_t rcIndex)
{
    NS_LOG_FUNCTION(this << event << (uint32_t)rcIndex);
 
    NS_LOG_INFO("SatUtMac::ReceiveQueueEventEssa - UT: " << m_nodeInfo->GetMacAddress()
                                                         << " time: " << Now().GetSeconds()
                                                         << " Queue: " << (uint32_t)rcIndex);
 
    // DoRandomAccess only if it is not scheduled yet
    // NOTE: could use m_nextPacketTime to do the check
    if (!m_isRandomAccessScheduled)
    {
        if (event == SatQueue::FIRST_BUFFERED_PKT || event == SatQueue::BUFFERED_PKT)
        {
            NS_LOG_INFO("SatUtMac::ReceiveQueueEventEssa - Buffered packet event received");
 
            if (m_randomAccess != nullptr)
            {
                NS_LOG_INFO("SatUtMac::ReceiveQueueEventEssa - Doing ESSA");
 
                DoRandomAccess(SatEnums::RA_TRIGGER_TYPE_ESSA);
            }
        }
    }
}
 
void
SatUtMac::SendLogon(Ptr<Packet> packet)
{
    SatPhy::PacketContainer_t packets;
    packets.push_back(packet);
 
    Ptr<SatSuperframeConf> superframeConf =
        m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE);
    uint8_t frameId = superframeConf->GetRaChannelFrameId(m_logonChannel);
    Ptr<SatFrameConf> frameConf = superframeConf->GetFrameConf(frameId);
 
    Ptr<SatTimeSlotConf> timeSlotConf = frameConf->GetTimeSlotConf(0);
 
    Ptr<SatWaveform> wf =
        m_superframeSeq->GetWaveformConf()->GetWaveform(timeSlotConf->GetWaveFormId());
    Time duration = wf->GetBurstDuration(frameConf->GetBtuConf()->GetSymbolRateInBauds());
 
    uint32_t carrierId = m_superframeSeq->GetCarrierId(SatConstVariables::SUPERFRAME_SEQUENCE,
                                                       frameId,
                                                       timeSlotConf->GetCarrierId());
 
    SatSignalParameters::txInfo_s txInfo;
    txInfo.packetType = SatEnums::PACKET_TYPE_LOGON;
    txInfo.modCod = wf->GetModCod();
    txInfo.sliceId = 0;
    txInfo.fecBlockSizeInBytes = wf->GetPayloadInBytes();
    txInfo.frameType = SatEnums::UNDEFINED_FRAME;
    txInfo.waveformId = wf->GetWaveformId();
 
    Time waitingTime = Seconds(m_waitingTimeLogonRng->GetValue(0.0,
                                                               pow(1 + m_sendLogonTries, 2) *
                                                                   m_windowInitLogon.GetSeconds()));
    m_sendLogonTries++;
    waitingTime = GetRealSendingTime(waitingTime);
    if (waitingTime >= Seconds(0))
    {
        Simulator::Schedule(waitingTime,
                            &SatUtMac::TransmitPackets,
                            this,
                            packets,
                            duration,
                            carrierId,
                            txInfo);
    }
 
    m_nextLogonTransmissionPossible =
        Simulator::Now() + m_maxWaitingTimeLogonResponse + waitingTime;
}
 
void
SatUtMac::Receive(SatPhy::PacketContainer_t packets, Ptr<SatSignalParameters> /*rxParams*/)
{
    NS_LOG_FUNCTION(this << packets.size());
 
    // Add packet trace entry:
    m_packetTrace(Simulator::Now(),
                  SatEnums::PACKET_RECV,
                  m_nodeInfo->GetNodeType(),
                  m_nodeInfo->GetNodeId(),
                  m_nodeInfo->GetMacAddress(),
                  SatEnums::LL_MAC,
                  SatEnums::LD_FORWARD,
                  SatUtils::GetPacketInfo(packets));
 
    // Invoke the `Rx` and `RxDelay` trace sources.
    RxTraces(packets);
 
    m_receptionDates.push(Simulator::Now());
    if (m_receptionDates.size() > 3)
    {
        m_receptionDates.pop();
    }
 
    for (SatPhy::PacketContainer_t::iterator i = packets.begin(); i != packets.end(); i++)
    {
        // Remove packet tag
        SatMacTag macTag;
        bool mSuccess = (*i)->PeekPacketTag(macTag);
        if (!mSuccess)
        {
            NS_FATAL_ERROR("MAC tag was not found from the packet!");
        }
 
        SatAddressE2ETag addressE2ETag;
        mSuccess = (*i)->PeekPacketTag(addressE2ETag);
        if (!mSuccess)
        {
            NS_FATAL_ERROR("SatAddressE2ETag was not found from the packet!");
        }
 
        NS_LOG_INFO("Packet from " << macTag.GetSourceAddress() << " to "
                                   << macTag.GetDestAddress());
        NS_LOG_INFO("Receiver " << m_nodeInfo->GetMacAddress());
 
        Mac48Address destAddress = macTag.GetDestAddress();
        if (destAddress == m_nodeInfo->GetMacAddress() || destAddress.IsBroadcast() ||
            destAddress.IsGroup())
        {
            // Remove control msg tag
            SatControlMsgTag ctrlTag;
            bool cSuccess = (*i)->PeekPacketTag(ctrlTag);
 
            if (cSuccess)
            {
                SatControlMsgTag::SatControlMsgType_t cType = ctrlTag.GetMsgType();
 
                if (cType != SatControlMsgTag::SAT_NON_CTRL_MSG)
                {
                    ReceiveSignalingPacket(*i);
                }
                else
                {
                    NS_FATAL_ERROR("A control message received with not valid msg type!");
                }
            }
            else if (destAddress.IsBroadcast())
            {
                // TODO: dummy frames and other broadcast needed to handle
                // dummy frames should ignored already in Phy layer
            }
            // Control msg tag not found, send the packet to higher layer
            else
            {
                // Pass the receiver address to LLC
                m_rxCallback(*i,
                             addressE2ETag.GetE2ESourceAddress(),
                             addressE2ETag.GetE2EDestAddress());
            }
        }
    }
}
 
void
SatUtMac::ReceiveSignalingPacket(Ptr<Packet> packet)
{
    NS_LOG_FUNCTION(this);
 
    // Remove the mac tag
    SatMacTag macTag;
    packet->PeekPacketTag(macTag);
 
    SatAddressE2ETag addressE2ETag;
    packet->PeekPacketTag(addressE2ETag);
 
    // Peek control msg tag
    SatControlMsgTag ctrlTag;
    bool cSuccess = packet->PeekPacketTag(ctrlTag);
 
    if (!cSuccess)
    {
        NS_FATAL_ERROR("SatControlMsgTag not found in the packet!");
    }
 
    switch (ctrlTag.GetMsgType())
    {
    case SatControlMsgTag::SAT_TBTP_CTRL_MSG: {
        uint32_t tbtpId = ctrlTag.GetMsgId();
 
        Ptr<SatTbtpMessage> tbtp = DynamicCast<SatTbtpMessage>(m_readCtrlCallback(tbtpId));

        if (tbtp == nullptr)
        {
            NS_FATAL_ERROR("TBTP not found, check SatBeamHelper::CtrlMsgStoreTimeInFwdLink "
                           "attribute is long enough!");
        }
 
        if (m_handoverState == WAITING_FOR_TBTP)
        {
            m_handoverState = NO_HANDOVER;
            m_firstTransmittableSuperframeId = tbtp->GetSuperframeCounter();
        }
        ScheduleTimeSlots(tbtp);
 
        packet->RemovePacketTag(macTag);
        packet->RemovePacketTag(addressE2ETag);
        packet->RemovePacketTag(ctrlTag);
 
        break;
    }
    case SatControlMsgTag::SAT_ARQ_ACK: {
        // ARQ ACK messages are forwarded to LLC, since they may be fragmented
        m_rxCallback(packet, addressE2ETag.GetE2ESourceAddress(), macTag.GetDestAddress());
        break;
    }
    case SatControlMsgTag::SAT_RA_CTRL_MSG: {
        uint32_t raCtrlId = ctrlTag.GetMsgId();
        Ptr<SatRaMessage> raMsg = DynamicCast<SatRaMessage>(m_readCtrlCallback(raCtrlId));
 
        if (raMsg != nullptr)
        {
            uint32_t allocationChannelId = raMsg->GetAllocationChannelId();
            uint16_t backoffProbability = raMsg->GetBackoffProbability();
            uint16_t backoffTime = raMsg->GetBackoffTime();
 
            NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress()
                               << "  Updating RA backoff probability for AC: "
                               << allocationChannelId << " to: " << backoffProbability);
 
            m_randomAccess->SetBackoffProbability(allocationChannelId, backoffProbability);
            m_randomAccess->SetBackoffTime(allocationChannelId, backoffTime);
 
            packet->RemovePacketTag(macTag);
            packet->RemovePacketTag(addressE2ETag);
            packet->RemovePacketTag(ctrlTag);
        }
        else
        {
            std::stringstream msg;
            msg << "Control message " << ctrlTag.GetMsgType()
                << " is not found from the FWD link control msg container!";
            msg << " at: " << Now().GetSeconds() << "s";
            Singleton<SatLog>::Get()->AddToLog(SatLog::LOG_WARNING, "", msg.str());
        }
        break;
    }
    case SatControlMsgTag::SAT_TIMU_CTRL_MSG: {
        uint32_t timuCtrlId = ctrlTag.GetMsgId();
        Ptr<SatTimuMessage> timuMsg = DynamicCast<SatTimuMessage>(m_readCtrlCallback(timuCtrlId));
 
        if (timuMsg != nullptr)
        {
            uint32_t beamId = timuMsg->GetAllocatedBeamId();
            uint32_t satId = timuMsg->GetAllocatedSatId();
            NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " switching from beam " << m_beamId
                               << " to beam " << beamId);
            if (m_beamId != beamId)
            {
                NS_LOG_INFO("Storing TIM-U information internally for later");
                m_timuInfo = Create<SatTimuInfo>(beamId,
                                                 satId,
                                                 timuMsg->GetSatAddress(),
                                                 timuMsg->GetGwAddress());
            }
        }
        else
        {
            std::stringstream msg;
            msg << "Control message " << ctrlTag.GetMsgType()
                << " is not found from the FWD link control msg container!";
            msg << " at: " << Now().GetSeconds() << "s";
            Singleton<SatLog>::Get()->AddToLog(SatLog::LOG_WARNING, "", msg.str());
        }
        break;
    }
    case SatControlMsgTag::SAT_SLICE_CTRL_MSG: {
        uint32_t sliceCtrlId = ctrlTag.GetMsgId();
        Ptr<SatSliceSubscriptionMessage> sliceMsg =
            DynamicCast<SatSliceSubscriptionMessage>(m_readCtrlCallback(sliceCtrlId));
 
        if (sliceMsg != nullptr)
        {
            if (m_nodeInfo->GetMacAddress() == sliceMsg->GetAddress())
            {
                m_sliceSubscriptionCallback(sliceMsg->GetSliceId());
            }
        }
        else
        {
            std::stringstream msg;
            msg << "Control message " << ctrlTag.GetMsgType()
                << " is not found from the FWD link control msg container!";
            msg << " at: " << Now().GetSeconds() << "s";
            Singleton<SatLog>::Get()->AddToLog(SatLog::LOG_WARNING, "", msg.str());
        }
        break;
    }
    case SatControlMsgTag::SAT_LOGON_RESPONSE_CTRL_MSG: {
        uint32_t logonId = ctrlTag.GetMsgId();
        Ptr<SatLogonResponseMessage> logonMsg =
            DynamicCast<SatLogonResponseMessage>(m_readCtrlCallback(logonId));
 
        if (logonMsg != nullptr)
        {
            m_raChannel = logonMsg->GetRaChannel();
            m_loggedOn = true;
            m_sendLogonTries = 0;
            m_rcstState.SetLogOffCallback(MakeCallback(&SatUtMac::LogOff, this));
            m_rcstState.SwitchToReadyForTdmaSync();
            m_deltaNcr = Simulator::Now().GetMicroSeconds() * m_clockDrift / 1000000.0;
        }
        else
        {
            std::stringstream msg;
            msg << "Control message " << ctrlTag.GetMsgType()
                << " is not found from the FWD link control msg container!";
            msg << " at: " << Now().GetSeconds() << "s";
            Singleton<SatLog>::Get()->AddToLog(SatLog::LOG_WARNING, "", msg.str());
        }
        break;
    }
    case SatControlMsgTag::SAT_NCR_CTRL_MSG: {
        uint32_t ncrCtrlId = ctrlTag.GetMsgId();
        Ptr<SatNcrMessage> ncrMsg = DynamicCast<SatNcrMessage>(m_readCtrlCallback(ncrCtrlId));
 
        m_lastNcrDateReceived = m_ncrV2 ? m_receptionDates.front() : Simulator::Now();
        m_ncr = ncrMsg->GetNcrDate();
        m_rcstState.NcrControlMessageReceived();
 
        if (m_rcstState.GetState() == SatUtMacState::RcstState_t::NCR_RECOVERY)
        {
            if (ControlMsgTransmissionPossible())
            {
                m_rcstState.SwitchToReadyForTdmaSync();
            }
            else
            {
                m_rcstState.SwitchToReadyForLogon();
            }
        }
        break;
    }
    case SatControlMsgTag::SAT_CMT_CTRL_MSG: {
        uint32_t cmtCtrlId = ctrlTag.GetMsgId();
        Ptr<SatCmtMessage> cmtMsg = DynamicCast<SatCmtMessage>(m_readCtrlCallback(cmtCtrlId));
        int16_t burstTimeCorrection = cmtMsg->GetBurstTimeCorrection();
        m_deltaNcr -= burstTimeCorrection;
        break;
    }
    case SatControlMsgTag::SAT_LOGOFF_CTRL_MSG: {
        uint32_t logoffCtrlId = ctrlTag.GetMsgId();
        Ptr<SatLogoffMessage> logoffMsg =
            DynamicCast<SatLogoffMessage>(m_readCtrlCallback(logoffCtrlId));
        LogOff();
        break;
    }
    default: {
        NS_FATAL_ERROR("SatUtMac received a non-supported control packet!");
        break;
    }
    }
}
 
void
SatUtMac::DoRandomAccess(SatEnums::RandomAccessTriggerType_t randomAccessTriggerType)
{
    NS_LOG_FUNCTION(this << randomAccessTriggerType);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress());
 
    if ((m_rcstState.GetState() != SatUtMacState::RcstState_t::TDMA_SYNC) && m_useLogon)
    {
        return;
    }

    m_isRandomAccessScheduled = false;
 
    SatRandomAccess::RandomAccessTxOpportunities_s txOpportunities;

    uint32_t allocationChannel = GetNextRandomAccessAllocationChannel();
 
    if (m_useLogon && allocationChannel == m_logonChannel)
    {
        NS_LOG_INFO("Logon channel cannot be used for RA transmition");
        return;
    }

    txOpportunities = m_randomAccess->DoRandomAccess(allocationChannel, randomAccessTriggerType);

    if (txOpportunities.txOpportunityType == SatEnums::RA_TX_OPPORTUNITY_SLOTTED_ALOHA)
    {
        Time txOpportunity = GetRealSendingTime(
            Time::FromInteger(txOpportunities.slottedAlohaTxOpportunity, Time::MS));
 
        NS_LOG_INFO("Processing Slotted ALOHA results, Tx evaluation @: "
                    << (Now() + txOpportunity).GetSeconds() << " seconds");

        if (txOpportunity >= Seconds(0))
        {
            Simulator::Schedule(txOpportunity,
                                &SatUtMac::ScheduleSlottedAlohaTransmission,
                                this,
                                allocationChannel);
        }
    }
    else if (txOpportunities.txOpportunityType == SatEnums::RA_TX_OPPORTUNITY_CRDSA)
    {
        NS_LOG_INFO("Processing CRDSA results");

        ScheduleCrdsaTransmission(allocationChannel, txOpportunities);
    }
    else if (txOpportunities.txOpportunityType == SatEnums::RA_TX_OPPORTUNITY_ESSA)
    {
        NS_LOG_INFO("SatUtMac::DoRandomAccess - Processing ESSA results");
        m_isRandomAccessScheduled = true;
        Time txOpportunity = GetRealSendingTime(
            Time::FromInteger(txOpportunities.slottedAlohaTxOpportunity, Time::MS));

        if (txOpportunity >= Seconds(0))
        {
            Simulator::Schedule(txOpportunity,
                                &SatUtMac::ScheduleEssaTransmission,
                                this,
                                allocationChannel);
        }
    }
}
 
uint32_t
SatUtMac::GetNextRandomAccessAllocationChannel()
{
    NS_LOG_FUNCTION(this);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " has allocation channel " << m_raChannel);

    return m_raChannel;
}
 
void
SatUtMac::ScheduleSlottedAlohaTransmission(uint32_t allocationChannel)
{
    NS_LOG_FUNCTION(this << allocationChannel);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " AC: " << allocationChannel);

    if (!m_tbtpContainer->HasScheduledTimeSlots())
    {
        NS_LOG_INFO("No known DAMA, selecting a slot for Slotted ALOHA");
 
        Ptr<SatSuperframeConf> superframeConf =
            m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE);
        uint8_t frameId = superframeConf->GetRaChannelFrameId(allocationChannel);
        Ptr<SatFrameConf> frameConf = superframeConf->GetFrameConf(frameId);
        uint32_t timeSlotCount = frameConf->GetTimeSlotCount();
 
        std::pair<bool, uint32_t> result = std::make_pair(false, 0);
        Time superframeStartTime =
            GetCurrentSuperFrameStartTime(SatConstVariables::SUPERFRAME_SEQUENCE);
 
        if (Now() < superframeStartTime)
        {
            NS_FATAL_ERROR("SatUtMac::ScheduleSlottedAlohaTransmission - Invalid SF start time");
        }
 
        uint32_t superFrameId = GetCurrentSuperFrameId(SatConstVariables::SUPERFRAME_SEQUENCE);
 
        NS_LOG_INFO("Searching for next available slot");

        while (!result.first)
        {
            NS_LOG_INFO("SuperFrameId: " << superFrameId << ", superframeStartTime: "
                                         << superframeStartTime.GetSeconds());
 
            result = SearchFrameForAvailableSlot(superframeStartTime,
                                                 frameConf,
                                                 timeSlotCount,
                                                 superFrameId,
                                                 allocationChannel);
 
            if (!result.first)
            {
                NS_LOG_INFO("Increasing frame offset!");
                superFrameId++;
                superframeStartTime += frameConf->GetDuration();
            }
        }

        Ptr<SatTimeSlotConf> timeSlotConf = frameConf->GetTimeSlotConf(result.second);

        Time slotStartTime = superframeStartTime + timeSlotConf->GetStartTime();
        Time offset = slotStartTime - Now();
 
        if (offset.IsStrictlyNegative())
        {
            NS_FATAL_ERROR("SatUtMac::ScheduleSlottedAlohaTransmission - Invalid transmit time: "
                           << offset.GetSeconds());
        }

        Ptr<SatWaveform> wf =
            m_superframeSeq->GetWaveformConf()->GetWaveform(timeSlotConf->GetWaveFormId());
        Time duration = wf->GetBurstDuration(frameConf->GetBtuConf()->GetSymbolRateInBauds());

        uint32_t carrierId =
            m_superframeSeq->GetCarrierId(0, frameId, timeSlotConf->GetCarrierId());
 
        NS_LOG_INFO("Starting to schedule, SF ID: "
                    << superFrameId << " slot: " << result.second
                    << " SF start: " << superframeStartTime.GetSeconds()
                    << " Tx start: " << (Now() + offset).GetSeconds()
                    << " duration: " << duration.GetSeconds() << " carrier ID: " << carrierId
                    << " payload in bytes: " << wf->GetPayloadInBytes());

        offset = GetRealSendingTime(offset);
        if (offset >= Seconds(0))
        {
            Simulator::Schedule(offset,
                                &SatUtMac::DoSlottedAlohaTransmit,
                                this,
                                duration,
                                wf,
                                carrierId,
                                uint8_t(SatEnums::CONTROL_FID),
                                SatUtScheduler::STRICT);
        }
    }
    else
    {
        NS_LOG_INFO("UT has known DAMA, aborting Slotted ALOHA");
    }
}
 
std::pair<bool, uint32_t>
SatUtMac::SearchFrameForAvailableSlot(Time superframeStartTime,
                                      Ptr<SatFrameConf> frameConf,
                                      uint32_t timeSlotCount,
                                      uint32_t superFrameId,
                                      uint32_t allocationChannel)
{
    NS_LOG_FUNCTION(this << superframeStartTime << timeSlotCount << superFrameId
                         << allocationChannel);
 
    Time opportunityOffset = Now() - superframeStartTime;
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress()
                       << " offset: " << opportunityOffset.GetSeconds());

    if (opportunityOffset.IsStrictlyNegative())
    {
        opportunityOffset = Seconds(0);
    }
 
    return FindNextAvailableRandomAccessSlot(opportunityOffset,
                                             frameConf,
                                             timeSlotCount,
                                             superFrameId,
                                             allocationChannel);
}
 
std::pair<bool, uint32_t>
SatUtMac::FindNextAvailableRandomAccessSlot(Time opportunityOffset,
                                            Ptr<SatFrameConf> frameConf,
                                            uint32_t timeSlotCount,
                                            uint32_t superFrameId,
                                            uint32_t allocationChannel)
{
    NS_LOG_FUNCTION(this << opportunityOffset << timeSlotCount << superFrameId
                         << allocationChannel);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress());
 
    Ptr<SatTimeSlotConf> slotConf;
    uint32_t slotId;
    bool availableSlotFound = false;

    for (slotId = 0; slotId < timeSlotCount; slotId++)
    {
        slotConf = frameConf->GetTimeSlotConf(slotId);
 
        // NS_LOG_INFO ("Slot: " << slotId <<
        //              " slot offset: " << slotConf->GetStartTime.GetSeconds () <<
        //              " opportunity offset: " << opportunityOffset.GetSeconds ());

        if (slotConf->GetStartTime() >= opportunityOffset)
        {
            if (UpdateUsedRandomAccessSlots(superFrameId, allocationChannel, slotId))
            {
                availableSlotFound = true;
                break;
            }
        }
    }
 
    NS_LOG_INFO("Success: " << availableSlotFound << " SF: " << superFrameId << " AC: "
                            << allocationChannel << " slot: " << slotId << "/" << timeSlotCount);
 
    return std::make_pair(availableSlotFound, slotId);
}
 
void
SatUtMac::ScheduleEssaTransmission(uint32_t allocationChannel)
{
    // TODO: do we really need the allocationChannel ???
    NS_LOG_FUNCTION(this << allocationChannel);
 
    NS_LOG_INFO("SatUtMac::ScheduleEssaTransmission - UT: " << m_nodeInfo->GetMacAddress()
                                                            << " time: " << Now().GetSeconds()
                                                            << " AC: " << allocationChannel);

    Time offset = m_nextPacketTime - Now();
 
    if (offset.IsStrictlyNegative())
    {
        offset = Seconds(0);
    }

    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); // only one timeslot on ESSA
 
    Ptr<SatWaveform> wf =
        m_superframeSeq->GetWaveformConf()->GetWaveform(timeSlotConf->GetWaveFormId());
    Time duration = wf->GetBurstDuration(frameConf->GetBtuConf()->GetSymbolRateInBauds());
 
    NS_LOG_INFO("SatUtMac::ScheduleEssaTransmission - Starting to schedule @ "
                << Now().GetSeconds() << " Tx start: " << (Now() + offset).GetSeconds()
                << " duration: " << duration.GetSeconds()
                << " payload in bytes: " << wf->GetPayloadInBytes());

    uint32_t carrierId = 0; // TODO: for now we use 0 as we have a single carrier

    offset = GetRealSendingTime(offset);
    if (offset >= Seconds(0))
    {
        Simulator::Schedule(offset,
                            &SatUtMac::DoEssaTransmit,
                            this,
                            duration,
                            wf,
                            carrierId,
                            uint8_t(SatEnums::CONTROL_FID),
                            SatUtScheduler::LOOSE);
    }
}
 
void
SatUtMac::ScheduleCrdsaTransmission(uint32_t allocationChannel,
                                    SatRandomAccess::RandomAccessTxOpportunities_s txOpportunities)
{
    NS_LOG_FUNCTION(this << allocationChannel);
 
    // get current superframe ID
    Time now = Simulator::Now();
    Time superFrameStart = GetCurrentSuperFrameStartTime(SatConstVariables::SUPERFRAME_SEQUENCE);
    uint32_t superFrameId = GetCurrentSuperFrameId(SatConstVariables::SUPERFRAME_SEQUENCE);
    NS_LOG_INFO("Checking for CRDSA transmission at "
                << now.GetMilliSeconds() - superFrameStart.GetMilliSeconds()
                << " milliseconds into superframe " << superFrameId);
 
    // TODO: check we didn't already scheduled packets for this superframe
    // (because we are moving so fast, for instance, that we are now at the end of the
    // window for this "past" superframe instead of the beginning of the next one)
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " AC: " << allocationChannel
                       << ", SF: " << superFrameId << ", num of opportunities: "
                       << txOpportunities.crdsaTxOpportunities.size());
 
    std::map<uint32_t, std::set<uint32_t>>::iterator iter;

    for (iter = txOpportunities.crdsaTxOpportunities.begin();
         iter != txOpportunities.crdsaTxOpportunities.end();
         iter++)
    {
        std::set<uint32_t>::iterator iterSet;

        for (iterSet = iter->second.begin(); iterSet != iter->second.end(); iterSet++)
        {
            if (!UpdateUsedRandomAccessSlots(superFrameId, allocationChannel, *iterSet))
            {
                NS_FATAL_ERROR(
                    "SatUtMac::ScheduleCrdsaTransmission - Slot unavailable: " << *iterSet);
            }
        }

        NS_LOG_INFO("Creating replicas for packet " << (uint32_t)m_crdsaUniquePacketId);
        CreateCrdsaPacketInstances(allocationChannel, iter->second);
    }
}
 
void
SatUtMac::CreateCrdsaPacketInstances(uint32_t allocationChannel, std::set<uint32_t> slots)
{
    NS_LOG_FUNCTION(this << allocationChannel);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " AC: " << allocationChannel);
 
    Ptr<SatSuperframeConf> superframeConf =
        m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE);
    uint8_t frameId = superframeConf->GetRaChannelFrameId(allocationChannel);
    Ptr<SatFrameConf> frameConf = superframeConf->GetFrameConf(frameId);

    Time superframeStartTime = Now();

    uint32_t payloadBytes = superframeConf->GetRaChannelTimeSlotPayloadInBytes(allocationChannel);

    payloadBytes -= m_randomAccess->GetCrdsaSignalingOverheadInBytes();
 
    if (payloadBytes < 1)
    {
        NS_FATAL_ERROR(
            "SatUtMac::CreateCrdsaPacketInstances - Not enough capacity in CRDSA payload");
    }

    SatUtScheduler::SatCompliancePolicy_t policy;
    if (m_crdsaOnlyForControl)
    {
        policy = SatUtScheduler::STRICT;
    }
    else
    {
        policy = SatUtScheduler::LOOSE;
    }

    SatPhy::PacketContainer_t uniq;
    ExtractPacketsToSchedule(uniq,
                             payloadBytes,
                             SatTimeSlotConf::SLOT_TYPE_TRC,
                             uint8_t(SatEnums::CONTROL_FID),
                             policy,
                             true);
 
    NS_LOG_INFO("Processing the packet container, fragments: " << uniq.size());
 
    if (!uniq.empty())
    {
        std::vector<std::pair<uint16_t, SatPhy::PacketContainer_t>> replicas;
        std::map<uint16_t, SatCrdsaReplicaTag> tags;
        std::set<uint32_t>::iterator iterSet;
 
        NS_LOG_INFO("Creating replicas for a packet");

        for (iterSet = slots.begin(); iterSet != slots.end(); iterSet++)
        {
            SatPhy::PacketContainer_t rep;
            SatPhy::PacketContainer_t::const_iterator it = uniq.begin();
 
            for (; it != uniq.end(); ++it)
            {
                rep.push_back((*it)->Copy());
                NS_LOG_INFO(
                    "Replica in slot: "
                    << (*iterSet) << ", original (HL packet) fragment UID: " << (*it)->GetUid()
                    << ", copied replica fragment (HL packet) UID: " << rep.back()->GetUid());
            }
 
            NS_LOG_INFO("One replica created");
 
            replicas.push_back(std::make_pair(*iterSet, rep));
        }
 
        NS_LOG_INFO("Creating replica tags");

        for (uint32_t i = 0; i < replicas.size(); i++)
        {
            SatCrdsaReplicaTag replicaTag;
 
            replicaTag.AddSlotId(replicas[i].first);
 
            NS_LOG_INFO("Own packet tag: " << replicas[i].first);
 
            for (uint32_t j = 0; j < replicas.size(); j++)
            {
                if (i != j)
                {
                    replicaTag.AddSlotId(replicas[j].first);
 
                    NS_LOG_INFO("Other packet tag: " << replicas[j].first);
                }
            }
            tags.insert(std::make_pair(replicas[i].first, replicaTag));
        }
 
        NS_LOG_INFO("Scheduling replicas");

        for (uint32_t i = 0; i < replicas.size(); i++)
        {
            for (uint32_t j = 0; j < replicas[i].second.size(); j++)
            {
                NS_LOG_INFO("Replica: " << i << ", fragment: " << j
                                        << ", key: " << replicas[i].first << ", tag: "
                                        << tags.at(replicas[i].first).GetSlotIds().at(0)
                                        << ", fragment (HL packet) UID: "
                                        << replicas[i].second.at(j)->GetUid());

                replicas[i].second.at(j)->AddPacketTag(tags.at(replicas[i].first));
            }

            Ptr<SatTimeSlotConf> timeSlotConf = frameConf->GetTimeSlotConf(replicas[i].first);

            Time slotDelay = superframeStartTime + timeSlotConf->GetStartTime();
            Time offset = slotDelay - Now();
 
            if (offset.IsStrictlyNegative())
            {
                NS_FATAL_ERROR("SatUtMac::CreateCrdsaPacketInstances - Invalid transmit time: "
                               << offset.GetSeconds());
            }

            Ptr<SatWaveform> wf =
                m_superframeSeq->GetWaveformConf()->GetWaveform(timeSlotConf->GetWaveFormId());
            Time duration = wf->GetBurstDuration(frameConf->GetBtuConf()->GetSymbolRateInBauds());

            uint32_t carrierId =
                m_superframeSeq->GetCarrierId(SatConstVariables::SUPERFRAME_SEQUENCE,
                                              frameId,
                                              timeSlotConf->GetCarrierId());

            SatSignalParameters::txInfo_s txInfo;
            txInfo.packetType = SatEnums::PACKET_TYPE_CRDSA;
            txInfo.modCod = wf->GetModCod();
            txInfo.sliceId = 0;
            txInfo.fecBlockSizeInBytes = wf->GetPayloadInBytes();
            txInfo.frameType = SatEnums::UNDEFINED_FRAME;
            txInfo.waveformId = wf->GetWaveformId();
            txInfo.crdsaUniquePacketId = m_crdsaUniquePacketId;

            offset = GetRealSendingTime(offset);
            if (offset >= Seconds(0))
            {
                Simulator::Schedule(offset,
                                    &SatUtMac::TransmitPackets,
                                    this,
                                    replicas[i].second,
                                    duration,
                                    carrierId,
                                    txInfo);
            }
            NS_LOG_INFO("Scheduled a replica in slot " << replicas[i].first << " with offset "
                                                       << offset.GetSeconds());
        }
        replicas.clear();
        tags.clear();
 
        m_crdsaUniquePacketId++;
    }
}
 
bool
SatUtMac::UpdateUsedRandomAccessSlots(uint32_t superFrameId,
                                      uint32_t allocationChannelId,
                                      uint32_t slotId)
{
    NS_LOG_FUNCTION(this << superFrameId << allocationChannelId << slotId);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " SF: " << superFrameId
                       << " AC: " << allocationChannelId << " slot: " << slotId);
 
    std::map<std::pair<uint32_t, uint32_t>, std::set<uint32_t>>::iterator iter;
    bool isSlotFree = false;

    RemovePastRandomAccessSlots(superFrameId);
 
    std::pair<uint32_t, uint32_t> key = std::make_pair(superFrameId, allocationChannelId);
 
    iter = m_usedRandomAccessSlots.find(key);
 
    if (iter == m_usedRandomAccessSlots.end())
    {
        std::set<uint32_t> txOpportunities{{slotId}};
        std::pair<std::map<std::pair<uint32_t, uint32_t>, std::set<uint32_t>>::iterator, bool>
            result;
        result = m_usedRandomAccessSlots.insert(std::make_pair(key, txOpportunities));
 
        if (result.second)
        {
            isSlotFree = true;
            NS_LOG_INFO("No saved SF, slot " << slotId << " saved in SF " << superFrameId);
        }
        else
        {
            NS_LOG_WARN("No saved SF but unable to create one");
        }
    }
    else
    {
        std::pair<std::set<uint32_t>::iterator, bool> result;
        result = iter->second.insert(slotId);
 
        if (result.second)
        {
            isSlotFree = true;
            NS_LOG_INFO("Saved SF exist, slot " << slotId << " saved in SF " << superFrameId);
        }
        else
        {
            NS_LOG_WARN("Saved SF exist but unable to add slot " << slotId);
        }
    }
    return isSlotFree;
}
 
void
SatUtMac::RemovePastRandomAccessSlots(uint32_t superFrameId)
{
    NS_LOG_FUNCTION(this << superFrameId);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress() << " SF: " << superFrameId);
 
    std::map<std::pair<uint32_t, uint32_t>, std::set<uint32_t>>::iterator iter;
 
    for (iter = m_usedRandomAccessSlots.begin(); iter != m_usedRandomAccessSlots.end();)
    {
        if (iter->first.first < superFrameId)
        {
            iter = m_usedRandomAccessSlots.erase(iter);
        }
        else
        {
            ++iter;
        }
    }
}
 
void
SatUtMac::PrintUsedRandomAccessSlots()
{
    NS_LOG_FUNCTION(this);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress());
    std::cout << "UT: " << m_nodeInfo->GetMacAddress() << std::endl;
 
    for (auto& iter : m_usedRandomAccessSlots)
    {
        for (auto& slot : iter.second)
        {
            std::cout << "SF: " << iter.first.first << " AC: " << iter.first.second
                      << " slot: " << slot << std::endl;
        }
    }
}
 
void
SatUtMac::DoFrameStart()
{
    NS_LOG_FUNCTION(this);
 
    NS_LOG_INFO("UT: " << m_nodeInfo->GetMacAddress());
 
    if (m_timuInfo != nullptr)
    {
        NS_LOG_INFO("Applying TIM-U parameters received during the previous frame");
 
        Ptr<SatBeamScheduler> srcScheduler = m_beamSchedulerCallback(m_satId, m_beamId);
 
        NS_LOG_INFO("UT handover, old satellite is " << m_satId << ", old beam is " << m_beamId);
 
        m_beamId = m_timuInfo->GetBeamId();
        m_satId = m_timuInfo->GetSatId();
 
        NS_LOG_INFO("UT handover, new satellite is " << m_satId << ", new beam is " << m_beamId);
 
        SatMac::SetBeamId(m_beamId);
        SatMac::SetSatId(m_satId);
 
        Address satAddress = m_timuInfo->GetSatAddress();
        Mac48Address satAddress48 = Mac48Address::ConvertFrom(satAddress);
        if (satAddress48 != m_satelliteAddress)
        {
            SetSatelliteAddress(satAddress48);
        }
 
        Ptr<SatTopology> satTopology = Singleton<SatTopology>::Get();
 
        satTopology->UpdateUtSatAndBeam(m_node, m_satId, m_beamId);
        Ptr<Node> gwNode = satTopology->GetGwFromBeam(m_beamId);
        satTopology->UpdateGwConnectedToUt(m_node, gwNode);
 
        Mac48Address gwAddress =
            Singleton<SatTopology>::Get()->GetGwAddressInUt(m_nodeInfo->GetNodeId());
        SetGwAddress(gwAddress);
        m_routingUpdateCallback(m_nodeInfo->GetMacAddress(), m_gwAddress);
 
        m_handoverCallback(m_satId, m_beamId);
 
        Ptr<SatBeamScheduler> dstScheduler = m_beamSchedulerCallback(m_satId, m_beamId);
        srcScheduler->DisconnectUt(m_nodeInfo->GetMacAddress());
        dstScheduler->ConnectUt(m_nodeInfo->GetMacAddress());
 
        Ptr<SatIdMapper> satIdMapper = Singleton<SatIdMapper>::Get();
        satIdMapper->UpdateMacToSatId(m_nodeInfo->GetMacAddress(), m_satId);
        satIdMapper->UpdateMacToBeamId(m_nodeInfo->GetMacAddress(), m_beamId);
        satTopology->UpdateUtSatAndBeam(m_node, m_satId, m_beamId);
        m_updateIslCallback();
 
        if (!m_updateAddressAndIdentifierCallback.IsNull())
        {
            m_updateAddressAndIdentifierCallback(m_node);
        }
 
        m_handoverModule->HandoverFinished();
 
        m_tbtpContainer->Clear();
        m_handoverState = WAITING_FOR_TBTP;
        m_timuInfo = nullptr;
    }
    else if (m_txCheckCallback())
    {
        NS_LOG_INFO("Tx is permitted");
 
        if (m_rcstState.GetState() == SatUtMacState::RcstState_t::HOLD_STANDBY)
        {
            m_rcstState.SwitchToOffStandby();
        }
 
        if (m_loggedOn && m_handoverModule != nullptr)
        {
            NS_LOG_INFO("UT checking for beam handover recommendation");
            if (m_handoverModule->CheckForHandoverRecommendation(m_satId, m_beamId))
            {
                if (m_handoverState == NO_HANDOVER)
                {
                    m_handoverState = HANDOVER_RECOMMENDATION_SENT;
                    m_handoverMessagesCount = 0;
                }
                else if (m_handoverState == HANDOVER_RECOMMENDATION_SENT)
                {
                    ++m_handoverMessagesCount;
                }
                if (m_useLogon && m_handoverMessagesCount > m_maxHandoverMessagesSent)
                {
                    m_handoverMessagesCount = 0;
                    LogOff();
 
                    Ptr<SatBeamScheduler> srcScheduler = m_beamSchedulerCallback(m_satId, m_beamId);
 
                    m_satId = m_handoverModule->GetAskedSatId();
                    m_beamId = m_handoverModule->GetAskedBeamId();
 
                    Ptr<SatTopology> satTopology = Singleton<SatTopology>::Get();
 
                    satTopology->UpdateUtSatAndBeam(m_node, m_satId, m_beamId);
                    Ptr<Node> gwNode = satTopology->GetGwFromBeam(m_beamId);
                    satTopology->UpdateGwConnectedToUt(m_node, gwNode);
 
                    Address satAddress =
                        m_beamSchedulerCallback(m_satId, m_beamId)->GetSatAddress();
                    Mac48Address satAddress48 = Mac48Address::ConvertFrom(satAddress);
                    if (satAddress48 != m_satelliteAddress)
                    {
                        SetSatelliteAddress(satAddress48);
                    }
 
                    Mac48Address gwAddress =
                        Singleton<SatTopology>::Get()->GetGwAddressInUt(m_nodeInfo->GetNodeId());
                    if (gwAddress != m_gwAddress)
                    {
                        SetGwAddress(gwAddress);
                        m_updateGwAddressCallback(gwAddress);
                        m_routingUpdateCallback(m_nodeInfo->GetMacAddress(), gwAddress);
                    }
                    m_handoverCallback(m_satId, m_beamId);
 
                    Ptr<SatBeamScheduler> dstScheduler = m_beamSchedulerCallback(m_satId, m_beamId);
                    srcScheduler->DisconnectUt(m_nodeInfo->GetMacAddress());
                    dstScheduler->ConnectUt(m_nodeInfo->GetMacAddress());
 
                    Ptr<SatIdMapper> satIdMapper = Singleton<SatIdMapper>::Get();
                    satIdMapper->UpdateMacToSatId(m_nodeInfo->GetMacAddress(), m_satId);
                    satIdMapper->UpdateMacToBeamId(m_nodeInfo->GetMacAddress(), m_beamId);
                    satTopology->UpdateUtSatAndBeam(m_node, m_satId, m_beamId);
                    m_updateIslCallback();
 
                    if (!m_updateAddressAndIdentifierCallback.IsNull())
                    {
                        m_updateAddressAndIdentifierCallback(m_node);
                    }
 
                    m_tbtpContainer->Clear();
                    m_handoverState = NO_HANDOVER;
                    m_nextLogonTransmissionPossible = Simulator::Now();
                }
            }
        }
 
        if (m_randomAccess != nullptr)
        {
            if (m_loggedOn)
            {
                // reset packet ID counter for this frame
                m_crdsaUniquePacketId = 1;
 
                // execute CRDSA trigger
                DoRandomAccess(SatEnums::RA_TRIGGER_TYPE_CRDSA);
            }
            else if (m_useLogon)
            {
                m_rcstState.SwitchToReadyForLogon();
                if (Simulator::Now() > m_nextLogonTransmissionPossible)
                {
                    // Do Logon
                    m_sendLogonCallback();
                }
            }
        }
    }
    else
    {
        NS_LOG_INFO("Tx is disabled");
        m_rcstState.SwitchToHoldStandby();
    }
 
    Time nextSuperFrameTxTime = GetNextSuperFrameTxTime(SatConstVariables::SUPERFRAME_SEQUENCE);
    NS_ASSERT_MSG(Now() < nextSuperFrameTxTime,
                  "Scheduling next superframe start time to the past!");
 
    Time schedulingDelay = nextSuperFrameTxTime - Now();
    Time realDelay = GetRealSendingTime(schedulingDelay);
    if (realDelay == Seconds(0))
    {
        schedulingDelay += m_superframeSeq->GetDuration(SatConstVariables::SUPERFRAME_SEQUENCE);
    }
    Simulator::Schedule(GetRealSendingTime(schedulingDelay), &SatUtMac::DoFrameStart, this);
}
 
Time
SatUtMac::GetRealSendingTime(Time t)
{
    if (m_deltaNcr == 0) // For some reason returning t-0 is different than returning t...
    {
        return t;
    }
 
    uint32_t driftTicks = (t + Simulator::Now()).GetMicroSeconds() * m_clockDrift / 1000000;
    int32_t deltaTicks = m_deltaNcr - driftTicks;
    Time deltaTime = NanoSeconds(deltaTicks * 1000 / 27.0);
 
    return t - deltaTime;
}
 
SatUtMac::SatTimuInfo::SatTimuInfo(uint32_t beamId,
                                   uint32_t satId,
                                   Address satAddress,
                                   Address gwAddress)
    : m_beamId(beamId),
      m_satId(satId),
      m_satAddress(satAddress),
      m_gwAddress(gwAddress)
{
    NS_LOG_FUNCTION(this << beamId << satAddress << gwAddress);
}
 
uint32_t
SatUtMac::SatTimuInfo::GetBeamId() const
{
    NS_LOG_FUNCTION(this);
    return m_beamId;
}
 
uint32_t
SatUtMac::SatTimuInfo::GetSatId() const
{
    NS_LOG_FUNCTION(this);
    return m_satId;
}
 
Address
SatUtMac::SatTimuInfo::GetSatAddress() const
{
    NS_LOG_FUNCTION(this);
    return m_satAddress;
}
 
Address
SatUtMac::SatTimuInfo::GetGwAddress() const
{
    NS_LOG_FUNCTION(this);
    return m_gwAddress;
}
 
SatUtMacState::RcstState_t
SatUtMac::GetRcstState() const
{
    NS_LOG_FUNCTION(this);
    return m_rcstState.GetState();
}
 
void
SatUtMac::ExtractPacketsToSchedule(SatPhy::PacketContainer_t& packets,
                                   uint32_t payloadBytes,
                                   SatTimeSlotConf::SatTimeSlotType_t type,
                                   uint8_t rcIndex,
                                   SatUtScheduler::SatCompliancePolicy_t policy,
                                   bool randomAccessChannel)
{
    NS_LOG_INFO(this << payloadBytes << type << rcIndex << policy << randomAccessChannel);
 
    uint32_t superFrameId = GetCurrentSuperFrameId(SatConstVariables::SUPERFRAME_SEQUENCE);
    if ((m_handoverState == NO_HANDOVER &&
         (randomAccessChannel || m_firstTransmittableSuperframeId <= superFrameId)) ||
        (randomAccessChannel && m_handoverState != HANDOVER_RECOMMENDATION_SENT))
    {
        NS_LOG_INFO("Regular scheduling");
        m_utScheduler->DoScheduling(packets, payloadBytes, type, rcIndex, policy);
    }
    else
    {
        NS_LOG_INFO("Handover recommendation sent, force control packets only");
        m_utScheduler->DoScheduling(packets,
                                    payloadBytes,
                                    SatTimeSlotConf::SLOT_TYPE_C,
                                    SatEnums::CONTROL_FID,
                                    SatUtScheduler::STRICT);
 
        // Remove every control packets except handover requests
        SatPhy::PacketContainer_t::iterator it = packets.begin();
        while (it != packets.end())
        {
            SatControlMsgTag ctrlTag;
            bool success = (*it)->PeekPacketTag(ctrlTag);
 
            if (success && ctrlTag.GetMsgType() == SatControlMsgTag::SAT_HR_CTRL_MSG)
            {
                ++it;
            }
            else
            {
                it = packets.erase(it);
            }
        }
    }
}
 
} // namespace ns3