satellite-beam-scheduler.cc

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/* -*- 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.com>
 */
 
#include "satellite-beam-scheduler.h"
 
#include "../stats/satellite-frame-symbol-load-probe.h"
#include "../stats/satellite-frame-user-load-probe.h"
#include "satellite-const-variables.h"
#include "satellite-control-message.h"
#include "satellite-dama-entry.h"
#include "satellite-default-superframe-allocator.h"
#include "satellite-id-mapper.h"
#include "satellite-lower-layer-service.h"
#include "satellite-rtn-link-time.h"
#include "satellite-superframe-allocator.h"
#include "satellite-superframe-sequence.h"
 
#include <ns3/address.h>
#include <ns3/boolean.h>
#include <ns3/double.h>
#include <ns3/enum.h>
#include <ns3/ipv4-address.h>
#include <ns3/log.h>
#include <ns3/mac48-address.h>
#include <ns3/singleton.h>
 
#include <algorithm>
#include <sstream>
#include <utility>
 
NS_LOG_COMPONENT_DEFINE("SatBeamScheduler");
 
namespace ns3
{
 
// UtInfo class declarations for SatBeamScheduler
SatBeamScheduler::SatUtInfo::SatUtInfo(Ptr<SatDamaEntry> damaEntry,
                                       Ptr<SatCnoEstimator> cnoEstimator,
                                       Time controlSlotOffset,
                                       bool controlSlotsEnabled)
    : m_damaEntry(damaEntry),
      m_cnoEstimator(cnoEstimator),
      m_controlSlotsEnabled(controlSlotsEnabled)
{
    NS_LOG_FUNCTION(this);
 
    SetControlSlotGenerationTime(controlSlotOffset);
}
 
Ptr<SatDamaEntry>
SatBeamScheduler::SatUtInfo::GetDamaEntry()
{
    NS_LOG_FUNCTION(this);
 
    return m_damaEntry;
}
 
void
SatBeamScheduler::SatUtInfo::UpdateDamaEntryFromCrs()
{
    NS_LOG_FUNCTION(this);
 
    // map to sum up RBDC requests per RC
    std::map<uint8_t, uint16_t> rbdcReqs;
 
    for (CrMsgContainer_t::const_iterator crIt = m_crContainer.begin(); crIt != m_crContainer.end();
         crIt++)
    {
        SatCrMessage::RequestContainer_t crContent = (*crIt)->GetCapacityRequestContent();
 
        for (SatCrMessage::RequestContainer_t::const_iterator descriptorIt = crContent.begin();
             descriptorIt != crContent.end();
             descriptorIt++)
        {
            switch (descriptorIt->first.second)
            {
            case SatEnums::DA_RBDC: {
                rbdcReqs[descriptorIt->first.first] += descriptorIt->second;
                break;
            }
 
            case SatEnums::DA_VBDC: {
                m_damaEntry->ResetVolumeBacklogPersistence();
                m_damaEntry->UpdateVbdcInBytes(descriptorIt->first.first, descriptorIt->second);
                break;
            }
 
            case SatEnums::DA_AVBDC: {
                m_damaEntry->ResetVolumeBacklogPersistence();
                m_damaEntry->SetVbdcInBytes(descriptorIt->first.first, descriptorIt->second);
                break;
            }
 
            default:
                break;
            }
        }
    }
 
    // update RBDC with summed up requests
    for (std::map<uint8_t, uint16_t>::iterator it = rbdcReqs.begin(); it != rbdcReqs.end(); it++)
    {
        m_damaEntry->ResetDynamicRatePersistence();
        m_damaEntry->UpdateRbdcInKbps(it->first, it->second);
    }
 
    // clear container when CRs processed
    m_crContainer.clear();
}
 
double
SatBeamScheduler::SatUtInfo::GetCnoEstimation()
{
    NS_LOG_FUNCTION(this);
 
    return m_cnoEstimator->GetCnoEstimation();
}
 
void
SatBeamScheduler::SatUtInfo::AddCnoSample(double sample)
{
    NS_LOG_FUNCTION(this << sample);
 
    m_cnoEstimator->AddSample(sample);
}
 
void
SatBeamScheduler::SatUtInfo::AddCrMsg(Ptr<SatCrMessage> crMsg)
{
    NS_LOG_FUNCTION(this << crMsg);
 
    m_crContainer.push_back(crMsg);
}
 
void
SatBeamScheduler::SatUtInfo::ClearCrMsgs()
{
    NS_LOG_FUNCTION(this);
 
    m_crContainer.clear();
}
 
bool
SatBeamScheduler::SatUtInfo::IsControlSlotGenerationTime() const
{
    NS_LOG_FUNCTION(this);
 
    bool isGenerationTime = false;
 
    if (m_controlSlotsEnabled && (m_controlSlotGenerationTime <= Simulator::Now()))
    {
        isGenerationTime = true;
    }
 
    return isGenerationTime;
}
 
void
SatBeamScheduler::SatUtInfo::SetControlSlotGenerationTime(Time offset)
{
    NS_LOG_FUNCTION(this);
 
    m_controlSlotGenerationTime = Simulator::Now() + offset;
}
 
// SatBeamScheduler
 
NS_OBJECT_ENSURE_REGISTERED(SatBeamScheduler);
 
TypeId
SatBeamScheduler::GetTypeId(void)
{
    static TypeId tid =
        TypeId("ns3::SatBeamScheduler")
            .SetParent<Object>()
            .AddConstructor<SatBeamScheduler>()
            .AddAttribute("CnoEstimationMode",
                          "Mode of the C/N0 estimator",
                          EnumValue(SatCnoEstimator::LAST),
                          MakeEnumAccessor(&SatBeamScheduler::m_cnoEstimatorMode),
                          MakeEnumChecker(SatCnoEstimator::LAST,
                                          "LastValueInWindow",
                                          SatCnoEstimator::MINIMUM,
                                          "MinimumValueInWindow",
                                          SatCnoEstimator::AVERAGE,
                                          "AverageValueInWindow"))
            .AddAttribute("CnoEstimationWindow",
                          "Time window for C/N0 estimation.",
                          TimeValue(MilliSeconds(1000)),
                          MakeTimeAccessor(&SatBeamScheduler::m_cnoEstimationWindow),
                          MakeTimeChecker())
            .AddAttribute("MaxTwoWayPropagationDelay",
                          "Maximum two way propagation delay between GW and UT.",
                          TimeValue(MilliSeconds(560)),
                          MakeTimeAccessor(&SatBeamScheduler::m_maxTwoWayPropagationDelay),
                          MakeTimeChecker())
            .AddAttribute("MaxTBTPTxAndProcessingDelay",
                          "Maximum TBTP transmission and processing delay at the GW.",
                          TimeValue(MilliSeconds(100)),
                          MakeTimeAccessor(&SatBeamScheduler::m_maxTbtpTxAndProcessingDelay),
                          MakeTimeChecker())
            .AddAttribute(
                "ControlSlotsEnabled",
                "Control slots generation enabled according to ControlSlotInterval attribute.",
                BooleanValue(false),
                MakeBooleanAccessor(&SatBeamScheduler::m_controlSlotsEnabled),
                MakeBooleanChecker())
            .AddAttribute("ControlSlotInterval",
                          "Time interval to generate time slots for the UT(s).",
                          TimeValue(MilliSeconds(1000)),
                          MakeTimeAccessor(&SatBeamScheduler::m_controlSlotInterval),
                          MakeTimeChecker())
            .AddAttribute("HandoverStrategy",
                          "Strategy used when performing handover to transfer capacity requests "
                          "and C/No informations",
                          EnumValue(SatBeamScheduler::BASIC),
                          MakeEnumAccessor(&SatBeamScheduler::m_handoverStrategy),
                          MakeEnumChecker(SatBeamScheduler::BASIC,
                                          "Basic",
                                          SatBeamScheduler::CHECK_GATEWAY,
                                          "CheckGateway"))
            .AddAttribute("SuperFrameAllocatorType",
                          "Type of SuperFrameAllocator",
                          EnumValue(SatEnums::DEFAULT_SUPERFRAME_ALLOCATOR),
                          MakeEnumAccessor(&SatBeamScheduler::m_superframeAllocatorType),
                          MakeEnumChecker(SatEnums::DEFAULT_SUPERFRAME_ALLOCATOR, "Default"))
            .AddTraceSource("BacklogRequestsTrace",
                            "Trace for backlog requests done to beam scheduler.",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_backlogRequestsTrace),
                            "ns3::SatBeamScheduler::BacklogRequestsTraceCallback")
            .AddTraceSource("WaveformTrace",
                            "Trace scheduled wave forms (called once per UT per round).",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_waveformTrace),
                            "ns3::SatBeamScheduler::WaveformTrace")
            .AddTraceSource("FrameUtLoadTrace",
                            "Trace UT load per the frame.",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_frameUtLoadTrace),
                            "ns3::SatFrameUserLoadProbe::FrameUserLoadCallback")
            .AddTraceSource("FrameLoadTrace",
                            "Trace load per the frame allocated symbols / total symbols.",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_frameLoadTrace),
                            "ns3::SatFrameSymbolLoadProbe::FrameSymbolLoadCallback")
            .AddTraceSource("UsableCapacityTrace",
                            "Trace usable capacity per beam in kbps.",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_usableCapacityTrace),
                            "ns3::SatBeamScheduler::UsableCapacityTraceCallback")
            .AddTraceSource("UnmetCapacityTrace",
                            "Trace unmet capacity per beam in kbps.",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_unmetCapacityTrace),
                            "ns3::SatBeamScheduler::UnmetCapacityTrace")
            .AddTraceSource("ExceedingCapacityTrace",
                            "Trace exceeding capacity per beam in kbps.",
                            MakeTraceSourceAccessor(&SatBeamScheduler::m_exceedingCapacityTrace),
                            "ns3::SatBeamScheduler::ExceedingCapacityTrace");
    return tid;
}
 
SatBeamScheduler::SatBeamScheduler()
    : m_beamId(0),
      m_superframeSeq(0),
      m_superFrameCounter(0),
      m_txCallback(),
      m_logonChannelIndex(1),
      m_cnoEstimatorMode(SatCnoEstimator::LAST),
      m_maxBbFrameSize(0),
      m_controlSlotsEnabled(false),
      m_superframeAllocatorType(SatEnums::DEFAULT_SUPERFRAME_ALLOCATOR),
      m_receivedSatelliteCnoSample(false)
{
    NS_LOG_FUNCTION(this);
}
 
SatBeamScheduler::~SatBeamScheduler()
{
    NS_LOG_FUNCTION(this);
}
 
void
SatBeamScheduler::DoDispose()
{
    NS_LOG_FUNCTION(this);
    m_txCallback.Nullify();
    Object::DoDispose();
}
 
bool
SatBeamScheduler::Send(Ptr<SatControlMessage> msg)
{
    NS_LOG_FUNCTION(this << msg);
 
    m_txCallback(msg, Mac48Address::GetBroadcast());
    return true;
}
 
bool
SatBeamScheduler::SendTo(Ptr<SatControlMessage> msg, Address utId)
{
    NS_LOG_FUNCTION(this << msg << utId);
 
    if (!HasUt(utId))
    {
        return false;
    }
 
    m_txCallback(msg, utId);
    return true;
}
 
bool
SatBeamScheduler::SendToSatellite(Ptr<SatControlMessage> msg, Address satelliteMac)
{
    NS_LOG_FUNCTION(this << msg << satelliteMac);
 
    m_txCallback(msg, satelliteMac);
    return true;
}
 
void
SatBeamScheduler::SetSendTbtpCallback(SendTbtpCallback cb)
{
    m_txTbtpCallback = cb;
}
 
void
SatBeamScheduler::Initialize(uint32_t beamId,
                             SatBeamScheduler::SendCtrlMsgCallback cb,
                             Ptr<SatSuperframeSeq> seq,
                             uint32_t maxFrameSizeInBytes,
                             Address gwAddress)
{
    NS_LOG_FUNCTION(this << beamId << &cb);
 
    m_satelliteCnoEstimator = CreateCnoEstimator();
 
    m_beamId = beamId;
    m_txCallback = cb;
    m_superframeSeq = seq;
    m_maxBbFrameSize = maxFrameSizeInBytes;
    m_gwAddress = gwAddress;
 
    Time totalDelay = m_maxTwoWayPropagationDelay + m_maxTbtpTxAndProcessingDelay;
    uint32_t sfCountOffset =
        (uint32_t)(totalDelay.GetInteger() / seq->GetDuration(0).GetInteger() + 1);
 
    // Scheduling starts after one empty super frame.
    m_superFrameCounter = Singleton<SatRtnLinkTime>::Get()->GetNextSuperFrameCount(
                              SatConstVariables::SUPERFRAME_SEQUENCE) +
                          sfCountOffset;
 
    m_raChRandomIndex = CreateObject<UniformRandomVariable>();
    m_raChRandomIndex->SetAttribute("Min", DoubleValue(0));
 
    // by default we give index 0, even if there is no RA channels configured.
    uint32_t maxIndex = 0;
 
    if (m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE)
            ->GetRaChannelCount() > 0)
    {
        maxIndex = m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE)
                       ->GetRaChannelCount() -
                   1;
    }
 
    m_raChRandomIndex->SetAttribute("Max", DoubleValue(maxIndex));
    m_logonChannelIndex = maxIndex + 1;
 
    // Create the superframeAllocator object
    switch (m_superframeAllocatorType)
    {
    case SatEnums::DEFAULT_SUPERFRAME_ALLOCATOR: {
        Ptr<SatDefaultSuperframeAllocator> superframeAllocator =
            CreateObject<SatDefaultSuperframeAllocator>(
                m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE));
        m_superframeAllocator = DynamicCast<SatSuperframeAllocator>(superframeAllocator);
        break;
    }
    default: {
        NS_FATAL_ERROR("Invalid SuperframeAllocatorType");
    }
    }
 
    NS_LOG_INFO("Initialized SatBeamScheduler");
 
    Time delay;
    Time txTime = Singleton<SatRtnLinkTime>::Get()->GetNextSuperFrameStartTime(
        SatConstVariables::SUPERFRAME_SEQUENCE);
 
    if (txTime > Now())
    {
        delay = txTime - Now();
    }
    else
    {
        NS_FATAL_ERROR("Trying to schedule a super frame in the past!");
    }
 
    Simulator::Schedule(delay, &SatBeamScheduler::Schedule, this);
}
 
uint32_t
SatBeamScheduler::AddUt(Address utId, Ptr<SatLowerLayerServiceConf> llsConf)
{
    NS_LOG_FUNCTION(this << utId);
 
    Ptr<SatDamaEntry> damaEntry = Create<SatDamaEntry>(llsConf);
 
    Time firstCtrlSlotInterval = m_controlSlotInterval;
 
    if (m_superframeSeq->GetDuration(SatConstVariables::SUPERFRAME_SEQUENCE) <
        m_controlSlotInterval)
    {
        Ptr<UniformRandomVariable> m_randomInterval = CreateObject<UniformRandomVariable>();
        uint32_t randomOffset = m_randomInterval->GetInteger(
            m_superframeSeq->GetDuration(SatConstVariables::SUPERFRAME_SEQUENCE).GetInteger(),
            m_controlSlotInterval.GetInteger());
 
        firstCtrlSlotInterval = Time(randomOffset);
    }
 
    Ptr<SatCnoEstimator> cnoEstimator = CreateCnoEstimator();
    Ptr<SatUtInfo> utInfo =
        Create<SatUtInfo>(damaEntry, cnoEstimator, firstCtrlSlotInterval, m_controlSlotsEnabled);
    AddUtInfo(utId, utInfo);
 
    m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE)->GetRaChannelCount();
 
    // return random RA channel index for the UT.
    uint32_t raChannel;
    do
    {
        raChannel = m_raChRandomIndex->GetInteger();
    } while (raChannel == m_logonChannelIndex);
 
    return raChannel;
}
 
void
SatBeamScheduler::AddUtInfo(Address utId, Ptr<SatUtInfo> utInfo)
{
    NS_LOG_FUNCTION(this << utId << utInfo);
 
    Ptr<SatDamaEntry> damaEntry = utInfo->GetDamaEntry();
 
    // this method call acts as CAC check, if allocation fails fatal error is occurred.
    m_superframeAllocator->ReserveMinimumRate(
        damaEntry->GetMinRateBasedBytes(m_superframeAllocator->GetSuperframeDuration()),
        m_controlSlotsEnabled);
 
    std::pair<UtInfoMap_t::iterator, bool> result = m_utInfos.insert(std::make_pair(utId, utInfo));
 
    if (result.second)
    {
        SatFrameAllocator::SatFrameAllocReqItemContainer_t reqContainer(
            damaEntry->GetRcCount(),
            SatFrameAllocator::SatFrameAllocReqItem());
        SatFrameAllocator::SatFrameAllocReq allocReq(reqContainer);
        allocReq.m_cno = NAN;
        allocReq.m_address = utId;
 
        m_utRequestInfos.push_back(std::make_pair(utId, allocReq));
    }
    else
    {
        NS_FATAL_ERROR("UT (Address: " << utId << ") already added to Beam scheduler.");
    }
}
 
void
SatBeamScheduler::RemoveUtInfo(UtInfoMap_t::iterator iterator)
{
    Address utId = iterator->first;
    Ptr<SatUtInfo> utInfo = iterator->second;
    m_utInfos.erase(iterator);
 
    UtReqInfoContainer_t::iterator it = m_utRequestInfos.begin();
    for (; it != m_utRequestInfos.end(); ++it)
    {
        if (it->first == utId)
        {
            m_utRequestInfos.erase(it);
            break;
        }
    }
 
    Ptr<SatDamaEntry> damaEntry = utInfo->GetDamaEntry();
    m_superframeAllocator->ReleaseMinimumRate(
        damaEntry->GetMinRateBasedBytes(m_superframeAllocator->GetSuperframeDuration()),
        m_controlSlotsEnabled);
}
 
bool
SatBeamScheduler::HasUt(Address utId)
{
    NS_LOG_FUNCTION(this << utId);
 
    UtInfoMap_t::iterator result = m_utInfos.find(utId);
    return result != m_utInfos.end();
}
 
void
SatBeamScheduler::UpdateUtCno(Address utId, double cno)
{
    NS_LOG_FUNCTION(this << utId << cno);
 
    if (HasUt(utId))
    {
        m_utInfos[utId]->AddCnoSample(cno);
    }
}
 
void
SatBeamScheduler::UpdateSatelliteCno(Address satelliteMac, double cno)
{
    NS_LOG_FUNCTION(this << satelliteMac << cno);
 
    m_satelliteCnoEstimator->AddSample(cno);
 
    m_satelliteMac = satelliteMac;
    m_receivedSatelliteCnoSample = true;
}
 
void
SatBeamScheduler::UtCrReceived(Address utId, Ptr<SatCrMessage> crMsg)
{
    NS_LOG_FUNCTION(this << utId << crMsg);
 
    if (HasUt(utId))
    {
        m_utInfos[utId]->AddCrMsg(crMsg);
    }
}
 
Ptr<SatCnoEstimator>
SatBeamScheduler::CreateCnoEstimator()
{
    NS_LOG_FUNCTION(this);
 
    Ptr<SatCnoEstimator> estimator = NULL;
 
    switch (m_cnoEstimatorMode)
    {
    case SatCnoEstimator::LAST:
    case SatCnoEstimator::MINIMUM:
    case SatCnoEstimator::AVERAGE:
        estimator = Create<SatBasicCnoEstimator>(m_cnoEstimatorMode, m_cnoEstimationWindow);
        break;
 
    default:
        NS_FATAL_ERROR("Not supported C/N0 estimation mode!!!");
        break;
    }
 
    return estimator;
}
 
void
SatBeamScheduler::SendCnoToSatellite()
{
    if (m_receivedSatelliteCnoSample)
    {
        double cno = m_satelliteCnoEstimator->GetCnoEstimation();
 
        Ptr<SatCnoReportMessage> cnoReportMessage = CreateObject<SatCnoReportMessage>();
        cnoReportMessage->SetCnoEstimate(cno);
 
        SendToSatellite(cnoReportMessage, m_satelliteMac);
    }
 
    m_receivedSatelliteCnoSample = false;
}
 
void
SatBeamScheduler::Schedule()
{
    NS_LOG_FUNCTION(this);
 
    uint32_t requestedKbpsSum(0);
    uint32_t offeredKbpsSum(0);
 
    // check that there is UTs to schedule
    if (m_utInfos.size() > 0)
    {
        requestedKbpsSum = UpdateDamaEntriesWithReqs();
 
        DoPreResourceAllocation();
 
        // generate time slots
        Ptr<SatTbtpMessage> firstTbtp =
            CreateObject<SatTbtpMessage>(SatConstVariables::SUPERFRAME_SEQUENCE);
        firstTbtp->SetSuperframeCounter(m_superFrameCounter);
 
        std::vector<Ptr<SatTbtpMessage>> tbtps;
        tbtps.push_back(firstTbtp);
 
        // Add RA slots (channels)
        AddRaChannels(tbtps);
 
        SatFrameAllocator::UtAllocInfoContainer_t utAllocs;
 
        // Add DA slots to TBTP(s)
        m_superframeAllocator->GenerateTimeSlots(tbtps,
                                                 m_maxBbFrameSize,
                                                 utAllocs,
                                                 m_waveformTrace,
                                                 m_frameUtLoadTrace,
                                                 m_frameLoadTrace);
 
        // update VBDC counter of the UT/RCs
        offeredKbpsSum += UpdateDamaEntriesWithAllocs(utAllocs);
 
        // send TBTPs
        uint16_t error = 0;
        for (std::vector<Ptr<SatTbtpMessage>>::const_iterator it = tbtps.begin(); it != tbtps.end();
             it++)
        {
            if ((*it)->GetSizeInBytes() > m_maxBbFrameSize)
            {
                ++error;
            }
            else
            {
                if (!m_txTbtpCallback.IsNull())
                {
                    m_txTbtpCallback(*it);
                }
                Send(*it);
            }
        }
 
        if (error)
        {
            NS_FATAL_ERROR("Too big for " << error << " TBTP messages");
        }
 
        NS_LOG_INFO("TBTP sent");
    }
 
    uint32_t usableCapacity = std::min(offeredKbpsSum, requestedKbpsSum);
    uint32_t unmetCapacity = requestedKbpsSum - usableCapacity;
    uint32_t exceedingCapacity =
        (uint32_t)(std::max(((double)(offeredKbpsSum)-requestedKbpsSum), 0.0) + 0.5);
    m_usableCapacityTrace(usableCapacity);
    m_unmetCapacityTrace(unmetCapacity);
    m_exceedingCapacityTrace(exceedingCapacity);
    ++m_superFrameCounter;
 
    SendCnoToSatellite();
 
    // re-schedule next TBTP sending (call of this function)
    Simulator::Schedule(m_superframeSeq->GetDuration(SatConstVariables::SUPERFRAME_SEQUENCE),
                        &SatBeamScheduler::Schedule,
                        this);
}
 
void
SatBeamScheduler::AddRaChannels(std::vector<Ptr<SatTbtpMessage>>& tbtpContainer)
{
    NS_LOG_FUNCTION(this);
 
    if (tbtpContainer.empty())
    {
        NS_FATAL_ERROR("TBTP container must contain at least one message.");
    }
 
    Ptr<SatTbtpMessage> tbtpToFill = tbtpContainer.back();
 
    Ptr<SatSuperframeConf> superFrameConf =
        m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE);
 
    int32_t prevFrameId = -1;
 
    for (uint32_t i = 0; i < superFrameConf->GetRaChannelCount(); i++)
    {
        uint8_t frameId = superFrameConf->GetRaChannelFrameId(i);
        Ptr<SatFrameConf> frameConf = superFrameConf->GetFrameConf(frameId);
        uint16_t timeSlotCount = frameConf->GetTimeSlotCount() / frameConf->GetCarrierCount();
 
        // In case of carrier belong to same frame than previous we don't need to check
        // size for frame info when adding slot to TBTP, so it is set to 0.
        uint32_t frameInfoSize = 0;
 
        if (prevFrameId != (int32_t)frameId)
        {
            // frame changes, so check size needed for frame info in TBTP too
            frameInfoSize = tbtpToFill->GetFrameInfoSize();
        }
 
        while (timeSlotCount > 0)
        {
            // Get max nb of time slots in this TBTP
            uint32_t timeSlotCountMaxFrame =
                (m_maxBbFrameSize - tbtpToFill->GetSizeInBytes() - frameInfoSize) /
                tbtpToFill->GetTimeSlotInfoSizeInBytes();
            if (timeSlotCountMaxFrame > timeSlotCount)
            {
                timeSlotCountMaxFrame = timeSlotCount;
            }
 
            tbtpToFill->SetRaChannel(i,
                                     superFrameConf->GetRaChannelFrameId(i),
                                     timeSlotCountMaxFrame);
            timeSlotCount -= timeSlotCountMaxFrame;
 
            // if still room, create new tbtp and do it again
            if (timeSlotCount > 0)
            {
                Ptr<SatTbtpMessage> newTbtp =
                    CreateObject<SatTbtpMessage>(tbtpToFill->GetSuperframeSeqId());
                newTbtp->SetSuperframeCounter(tbtpToFill->GetSuperframeCounter());
                tbtpContainer.push_back(newTbtp);
                tbtpToFill = newTbtp;
            }
        }
    }
}
 
uint32_t
SatBeamScheduler::UpdateDamaEntriesWithReqs()
{
    NS_LOG_FUNCTION(this);
 
    uint32_t requestedCraRbdcKbps(0);
 
    for (UtReqInfoContainer_t::iterator it = m_utRequestInfos.begin(); it != m_utRequestInfos.end();
         it++)
    {
        // estimation of the C/N0 is done when scheduling UT
        Ptr<SatDamaEntry> damaEntry = m_utInfos.at(it->first)->GetDamaEntry();
 
        // process received CRs
        m_utInfos.at(it->first)->UpdateDamaEntryFromCrs();
 
        // update allocation request information to be used later to request capacity from frame
        // allocator
        it->second.m_cno = m_utInfos.at(it->first)->GetCnoEstimation();
 
        // set control slot generation on or off
        it->second.m_generateCtrlSlot = m_utInfos.at(it->first)->IsControlSlotGenerationTime();
 
        for (uint8_t i = 0; i < damaEntry->GetRcCount(); i++)
        {
            double superFrameDurationInSeconds =
                m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE)
                    ->GetDuration()
                    .GetSeconds();
 
            it->second.m_reqPerRc[i].m_craBytes =
                (SatConstVariables::BITS_IN_KBIT * damaEntry->GetCraInKbps(i) *
                 superFrameDurationInSeconds) /
                (double)(SatConstVariables::BITS_PER_BYTE);
            it->second.m_reqPerRc[i].m_rbdcBytes =
                (SatConstVariables::BITS_IN_KBIT * damaEntry->GetRbdcInKbps(i) *
                 superFrameDurationInSeconds) /
                (double)(SatConstVariables::BITS_PER_BYTE);
            it->second.m_reqPerRc[i].m_vbdcBytes = damaEntry->GetVbdcInBytes(i);
 
            // Collect the requested rate for all UTs per beam
            requestedCraRbdcKbps += damaEntry->GetCraInKbps(i);
            requestedCraRbdcKbps += damaEntry->GetRbdcInKbps(i);
 
            uint16_t minRbdcCraDeltaRateInKbps =
                std::max(0, damaEntry->GetMinRbdcInKbps(i) - damaEntry->GetCraInKbps(i));
            it->second.m_reqPerRc[i].m_minRbdcBytes =
                (SatConstVariables::BITS_IN_KBIT * minRbdcCraDeltaRateInKbps *
                 superFrameDurationInSeconds) /
                (double)(SatConstVariables::BITS_PER_BYTE);
 
            // if UT is not requesting any RBDC for this RC then set minimum RBDC 0
            // This means that no RBDC is actively requested for this RC
            if (it->second.m_reqPerRc[i].m_rbdcBytes == 0)
            {
                it->second.m_reqPerRc[i].m_minRbdcBytes = 0;
            }
 
            NS_ASSERT(
                (it->second.m_reqPerRc[i].m_minRbdcBytes <= it->second.m_reqPerRc[i].m_rbdcBytes));
 
            // it->second.m_reqPerRc[i].m_rbdcBytes =
            // std::max(it->second.m_reqPerRc[i].m_minRbdcBytes,
            // it->second.m_reqPerRc[i].m_rbdcBytes);
 
            // write backlog requests traces starts ...
            std::stringstream head;
            head << Now().GetSeconds() << ", ";
            head << m_beamId << ", ";
            head << Singleton<SatIdMapper>::Get()->GetUtIdWithMac(it->first) << ", ";
 
            std::stringstream rbdcTail;
            rbdcTail << SatEnums::DA_RBDC << ", ";
            rbdcTail << damaEntry->GetRbdcInKbps(i);
 
            m_backlogRequestsTrace(head.str() + rbdcTail.str());
 
            std::stringstream vbdcTail;
            vbdcTail << SatEnums::DA_VBDC << ", ";
            vbdcTail << damaEntry->GetVbdcInBytes(i);
 
            m_backlogRequestsTrace(head.str() + vbdcTail.str());
            // ... write backlog requests traces ends
        }
    }
 
    return requestedCraRbdcKbps;
}
 
void
SatBeamScheduler::DoPreResourceAllocation()
{
    NS_LOG_FUNCTION(this);
 
    if (m_utInfos.size() > 0)
    {
        // sort UT requests according to C/N0 of the UTs
        m_utRequestInfos.sort(CnoCompare(m_utInfos));
 
        SatFrameAllocator::SatFrameAllocContainer_t allocReqs;
 
        for (UtReqInfoContainer_t::iterator it = m_utRequestInfos.begin();
             it != m_utRequestInfos.end();
             it++)
        {
            allocReqs.push_back(&(it->second));
        }
 
        // request capacity for UTs from frame allocator
        m_superframeAllocator->PreAllocateSymbols(allocReqs);
    }
}
 
uint32_t
SatBeamScheduler::UpdateDamaEntriesWithAllocs(
    SatFrameAllocator::UtAllocInfoContainer_t& utAllocContainer)
{
    NS_LOG_FUNCTION(this);
 
    uint32_t offeredCraRbdcKbps(0);
 
    for (UtReqInfoContainer_t::iterator it = m_utRequestInfos.begin(); it != m_utRequestInfos.end();
         it++)
    {
        Ptr<SatDamaEntry> damaEntry = m_utInfos.at(it->first)->GetDamaEntry();
        SatFrameAllocator::UtAllocInfoContainer_t::const_iterator allocInfo =
            utAllocContainer.find(it->first);
 
        if (allocInfo != utAllocContainer.end())
        {
            // update time to send next control slot, if control slot is allocated
            if (allocInfo->second.second)
            {
                m_utInfos.at(allocInfo->first)->SetControlSlotGenerationTime(m_controlSlotInterval);
            }
 
            double superFrameDurationInSeconds =
                m_superframeSeq->GetSuperframeConf(SatConstVariables::SUPERFRAME_SEQUENCE)
                    ->GetDuration()
                    .GetSeconds();
 
            for (uint32_t i = 0; i < allocInfo->second.first.size(); i++)
            {
                uint32_t rateBasedBytes =
                    (SatConstVariables::BITS_IN_KBIT * damaEntry->GetCraInKbps(i) *
                     superFrameDurationInSeconds) /
                    (double)(SatConstVariables::BITS_PER_BYTE);
                rateBasedBytes += (SatConstVariables::BITS_IN_KBIT * damaEntry->GetRbdcInKbps(i) *
                                   superFrameDurationInSeconds) /
                                  (double)(SatConstVariables::BITS_PER_BYTE);
 
                offeredCraRbdcKbps += (uint32_t)((allocInfo->second.first[i] *
                                                  (double)(SatConstVariables::BITS_PER_BYTE) /
                                                  superFrameDurationInSeconds /
                                                  (double)(SatConstVariables::BITS_IN_KBIT)) +
                                                 0.5);
 
                NS_LOG_INFO("UT: " << allocInfo->first << " RC index: " << i
                                   << " rate based bytes: " << rateBasedBytes
                                   << " allocated bytes: " << allocInfo->second.first[i]);
 
                // The scheduler has allocated more than the rate based bytes (CRA+RBDC)
                if (rateBasedBytes < allocInfo->second.first[i])
                {
                    // Requested VBDC
                    uint32_t vbdcBytes = damaEntry->GetVbdcInBytes(i);
 
                    NS_LOG_INFO("UT: " << allocInfo->first << " RC index: " << i
                                       << " requested VBDC bytes: " << vbdcBytes);
 
                    // Allocated VBDC for this RC index
                    uint32_t allocVbdcBytes = allocInfo->second.first[i] - rateBasedBytes;
 
                    // Allocated less than requested
                    if (vbdcBytes > allocVbdcBytes)
                    {
                        uint32_t remainingVbdcBytes = vbdcBytes - allocVbdcBytes;
 
                        NS_LOG_INFO("UT: " << allocInfo->first << " RC index: " << i
                                           << " VBDC allocation: " << allocVbdcBytes
                                           << " remaining VBDC bytes: " << remainingVbdcBytes);
 
                        damaEntry->SetVbdcInBytes(i, remainingVbdcBytes);
                    }
                    // Allocated more or equal to requested bytes
                    else
                    {
                        NS_LOG_INFO("UT: " << allocInfo->first << " RC index: " << i
                                           << " VBDC allocation: " << allocVbdcBytes
                                           << " remaining VBDC bytes: " << 0);
 
                        damaEntry->SetVbdcInBytes(i, 0);
                    }
                }
            }
        }
        // decrease persistence values
        damaEntry->DecrementDynamicRatePersistence();
        damaEntry->DecrementVolumeBacklogPersistence();
    }
    return offeredCraRbdcKbps;
}
 
void
SatBeamScheduler::TransferUtToBeam(Address utId, Ptr<SatBeamScheduler> destination)
{
    NS_LOG_FUNCTION(this << utId << destination->m_beamId);
 
    UtInfoMap_t::iterator utIterator = m_utInfos.find(utId);
    if (utIterator == m_utInfos.end())
    {
        // Check if handover already happened
        NS_ASSERT_MSG(destination->HasUt(utId), "UT is not part of the source beam");
    }
    else
    {
        // Moving UT infos between beams
        Ptr<SatUtInfo> utInfo = utIterator->second;
        destination->AddUtInfo(utId, utInfo);
        RemoveUtInfo(utIterator);
 
        // Handling capacity requests left and C/No estimations
        switch (m_handoverStrategy)
        {
        case BASIC: {
            utInfo->ClearCrMsgs();
            break;
        }
        case CHECK_GATEWAY: {
            if (m_gwAddress != destination->m_gwAddress)
            {
                utInfo->ClearCrMsgs();
            }
            break;
        }
        default:
            NS_FATAL_ERROR("Unknown handover strategy");
        }
    }
}
 
void
SatBeamScheduler::RemoveUt(Address utId)
{
    NS_LOG_FUNCTION(this << utId);
 
    UtInfoMap_t::iterator utIterator = m_utInfos.find(utId);
    if (utIterator == m_utInfos.end())
    {
        NS_FATAL_ERROR("Trying to remove a UT not connected to a beam: " << utId);
    }
 
    // Moving UT infos between beams
    Ptr<SatUtInfo> utInfo = utIterator->second;
    RemoveUtInfo(utIterator);
}
 
Ptr<SatTimuMessage>
SatBeamScheduler::CreateTimu() const
{
    NS_LOG_FUNCTION(this);
 
    Ptr<SatTimuMessage> timuMsg = CreateObject<SatTimuMessage>();
    timuMsg->SetAllocatedBeamId(m_beamId);
    timuMsg->SetGwAddress(m_gwAddress);
    return timuMsg;
}
 
void
SatBeamScheduler::ReserveLogonChannel(uint32_t logonChannelId)
{
    NS_LOG_FUNCTION(this << logonChannelId);
 
    DoubleValue maxId;
    m_raChRandomIndex->GetAttribute("Max", maxId);
    uint32_t maxIndex = maxId.Get();
 
    if (logonChannelId > maxIndex)
    {
        NS_FATAL_ERROR("Cannot use channel ID " << logonChannelId
                                                << " for logon as it doesn't exist");
    }
 
    if (maxIndex != 0)
    {
        // Allows to still return the channel 0 as the random access
        // channel for UTs without entering in an infinite loop in AddUt
        m_logonChannelIndex = logonChannelId;
    }
}
 
} // namespace ns3