satellite-bbframe-container.cc

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013 Magister Solutions Ltd
 *
 * 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>
 */
 
#include "satellite-bbframe-container.h"
 
#include "satellite-const-variables.h"
#include "satellite-utils.h"
 
#include "ns3/enum.h"
#include "ns3/log.h"
 
#include <algorithm>
#include <cmath>
#include <deque>
#include <random>
#include <utility>
#include <vector>
 
NS_LOG_COMPONENT_DEFINE("SatBbFrameContainer");
 
namespace ns3
{
 
NS_OBJECT_ENSURE_REGISTERED(SatBbFrameContainer);
 
SatBbFrameContainer::SatBbFrameContainer()
    : m_totalDuration(Seconds(0)),
      m_defaultBbFrameType(SatEnums::NORMAL_FRAME)
{
    NS_LOG_FUNCTION(this);
    NS_FATAL_ERROR("Default constructor of SatBbFrameContainer not supported.");
}
 
SatBbFrameContainer::SatBbFrameContainer(std::vector<SatEnums::SatModcod_t>& modcodsInUse,
                                         Ptr<SatBbFrameConf> conf)
    : m_totalDuration(Seconds(0)),
      m_bbFrameConf(conf),
      m_maxSymbolRate(conf->GetSymbolRate())
{
    NS_LOG_FUNCTION(this);
 
    for (std::vector<SatEnums::SatModcod_t>::const_iterator it = modcodsInUse.begin();
         it != modcodsInUse.end();
         it++)
    {
        std::pair<FrameContainer_t::iterator, bool> result =
            m_container.insert(std::make_pair(*it, std::deque<Ptr<SatBbFrame>>()));
 
        if (result.second == false)
        {
            NS_FATAL_ERROR("Queue for MODCOD: " << *it << " already exists!!!");
        }
    }
 
    m_defaultBbFrameType = SatEnums::NORMAL_FRAME;
 
    if (m_bbFrameConf->GetBbFrameUsageMode() == SatEnums::SHORT_FRAMES)
    {
        m_defaultBbFrameType = SatEnums::SHORT_FRAME;
    }
}
 
SatBbFrameContainer::~SatBbFrameContainer()
{
    NS_LOG_FUNCTION(this);
 
    m_container.clear();
}
 
TypeId
SatBbFrameContainer::GetTypeId(void)
{
    static TypeId tid =
        TypeId("ns3::SatBbFrameContainer")
            .SetParent<Object>()
            .AddConstructor<SatBbFrameContainer>()
            .AddTraceSource("BBFrameMergeTrace",
                            "Trace for merged BB Frames.",
                            MakeTraceSourceAccessor(&SatBbFrameContainer::m_bbFrameMergeTrace),
                            "ns3::SatBbFrame::BbFrameMergeCallback");
    return tid;
}
 
SatEnums::SatModcod_t
SatBbFrameContainer::GetModcod(uint32_t priorityClass, double cno)
{
    NS_LOG_FUNCTION(this);
 
    SatEnums::SatModcod_t modcod = m_bbFrameConf->GetDefaultModCod();
 
    if (priorityClass == 0)
    {
        modcod = m_bbFrameConf->GetMostRobustModcod(m_defaultBbFrameType);
    }
    else if (std::isnan(cno) == false)
    {
        modcod = m_bbFrameConf->GetBestModcod(cno, m_defaultBbFrameType);
    }
 
    return modcod;
}
 
uint32_t
SatBbFrameContainer::GetMaxFramePayloadInBytes(uint32_t priorityClass, SatEnums::SatModcod_t modcod)
{
    NS_LOG_FUNCTION(this);
 
    uint32_t payloadBytes = 0;
 
    if (priorityClass > 0)
    {
        payloadBytes = m_bbFrameConf->GetBbFramePayloadBits(modcod, m_defaultBbFrameType) /
                       SatConstVariables::BITS_PER_BYTE;
    }
    else
    {
        payloadBytes = m_bbFrameConf->GetBbFramePayloadBits(
                           m_bbFrameConf->GetMostRobustModcod(m_defaultBbFrameType),
                           m_defaultBbFrameType) /
                       SatConstVariables::BITS_PER_BYTE;
    }
 
    return payloadBytes;
}
 
uint32_t
SatBbFrameContainer::GetBytesLeftInTailFrame(uint32_t priorityClass, SatEnums::SatModcod_t modcod)
{
    NS_LOG_FUNCTION(this);
 
    uint32_t bytesLeft = GetMaxFramePayloadInBytes(priorityClass, modcod);
 
    if (priorityClass > 0)
    {
        if (m_container.at(modcod).empty() != true)
        {
            bytesLeft -= m_container.at(modcod).back()->GetSpaceUsedInBytes();
        }
        else
        {
            bytesLeft -= m_bbFrameConf->GetBbFrameHeaderSizeInBytes();
        }
    }
    else
    {
        if (m_ctrlContainer.empty() != true)
        {
            bytesLeft -= m_ctrlContainer.back()->GetSpaceUsedInBytes();
        }
        else
        {
            bytesLeft -= m_bbFrameConf->GetBbFrameHeaderSizeInBytes();
        }
    }
 
    return bytesLeft;
}
 
bool
SatBbFrameContainer::IsEmpty(uint32_t priorityClass, SatEnums::SatModcod_t modcod)
{
    NS_LOG_FUNCTION(this);
 
    if (priorityClass > 0)
    {
        return m_container.at(modcod).empty();
    }
    else
    {
        return m_ctrlContainer.empty();
    }
}
 
void
SatBbFrameContainer::AddData(uint32_t priorityClass, SatEnums::SatModcod_t modcod, Ptr<Packet> data)
{
    NS_LOG_FUNCTION(this);
 
    if (priorityClass > 0)
    {
        if ((m_container.at(modcod).empty()) ||
            (GetBytesLeftInTailFrame(priorityClass, modcod) < data->GetSize()))
        {
            CreateFrameToTail(priorityClass, modcod);
        }
        else if ((m_bbFrameConf->GetBbFrameUsageMode() == SatEnums::SHORT_AND_NORMAL_FRAMES) &&
                 (m_container.at(modcod).back()->GetFrameType() == SatEnums::SHORT_FRAME))
        {
            m_totalDuration += m_container.at(modcod).back()->Extend(m_bbFrameConf);
        }
        m_container.at(modcod).back()->AddPayload(data);
    }
    else
    {
        if (m_ctrlContainer.empty() ||
            GetBytesLeftInTailFrame(priorityClass, modcod) < data->GetSize())
        {
            // create and add frame to tail
            CreateFrameToTail(priorityClass,
                              m_bbFrameConf->GetMostRobustModcod(m_defaultBbFrameType));
        }
        else if ((m_bbFrameConf->GetBbFrameUsageMode() == SatEnums::SHORT_AND_NORMAL_FRAMES) &&
                 (m_container.at(modcod).back()->GetFrameType() == SatEnums::SHORT_FRAME))
        {
            m_totalDuration += m_ctrlContainer.back()->Extend(m_bbFrameConf);
        }
        m_ctrlContainer.back()->AddPayload(data);
    }
}
 
Time
SatBbFrameContainer::GetTotalDuration() const
{
    return m_totalDuration;
}
 
uint32_t
SatBbFrameContainer::GetFrameSymbols(SatEnums::SatModcod_t modcod)
{
    return m_bbFrameConf->GetBbFrameDuration(modcod, m_defaultBbFrameType).GetSeconds() *
           m_bbFrameConf->GetSymbolRate();
}
 
void
SatBbFrameContainer::SetMaxSymbolRate(uint32_t maxSymbolRate)
{
    m_maxSymbolRate = maxSymbolRate;
}
 
uint32_t
SatBbFrameContainer::GetMaxSymbolRate()
{
    return m_maxSymbolRate;
}
 
void
SatBbFrameContainer::ClearAllFrames()
{
    NS_LOG_FUNCTION(this);
 
    m_ctrlContainer.clear();
    for (FrameContainer_t::iterator it = m_container.begin(); it != m_container.end(); ++it)
    {
        it->second.clear();
    }
}
 
Ptr<SatBbFrame>
SatBbFrameContainer::GetNextFrame()
{
    Ptr<SatBbFrame> nextFrame = nullptr;
 
    if (m_ctrlContainer.empty() == false)
    {
        nextFrame = m_ctrlContainer.front();
        m_ctrlContainer.pop_front();
        m_totalDuration -= nextFrame->GetDuration();
    }
    else
    {
        std::vector<std::deque<Ptr<SatBbFrame>>*> nonEmptyQueues;
 
        for (FrameContainer_t::iterator it = m_container.begin(); it != m_container.end(); ++it)
        {
            if ((*it).second.empty() == false)
            {
                nonEmptyQueues.push_back(&it->second);
            }
        }
 
        if (nonEmptyQueues.empty() == false)
        {
            std::default_random_engine rng = std::default_random_engine{};
            std::shuffle(nonEmptyQueues.begin(), nonEmptyQueues.end(), rng);
 
            nextFrame = (*nonEmptyQueues.begin())->front();
            (*nonEmptyQueues.begin())->pop_front();
            m_totalDuration -= nextFrame->GetDuration();
        }
    }
 
    return nextFrame;
}
 
void
SatBbFrameContainer::CreateFrameToTail(uint32_t priorityClass, SatEnums::SatModcod_t modcod)
{
    NS_LOG_FUNCTION(this << modcod);
 
    Ptr<SatBbFrame> frame = Create<SatBbFrame>(modcod, m_defaultBbFrameType, m_bbFrameConf);
 
    if (frame != nullptr)
    {
        if (priorityClass > 0)
        {
            m_container.at(modcod).push_back(frame);
        }
        else
        {
            m_ctrlContainer.push_back(frame);
        }
 
        m_totalDuration += frame->GetDuration();
    }
    else
    {
        NS_FATAL_ERROR("BB Frame creation failed!!!");
    }
}
 
void
SatBbFrameContainer::MergeBbFrames(double carrierBandwidthInHz)
{
    // go through all BB Frame containers from the most efficient to the robust
    for (FrameContainer_t::reverse_iterator itFromMerge = m_container.rbegin();
         itFromMerge != m_container.rend();
         itFromMerge++)
    {
        // BB Frames currently exists in the BB Frame container for this MODCOD.
        if (itFromMerge->second.empty() == false)
        {
            // Get occupancy i.e. ratio of used space to maximum space in buffer at the back of the
            // list. Occupancy is not necessarily efficiency.
            double occupancy = itFromMerge->second.back()->GetOccupancy();
 
            // GetBbFrameHighOccupancyThreshold () returns a configured parameter. Part of a
            // high-low threshold hysteresis damper. Current occupancy is no good. Need to off load
            // the contents to some other BB Frame.
            if (occupancy < m_bbFrameConf->GetBbFrameHighOccupancyThreshold())
            {
                // weighted occupancy takes into account the spectra efficiency of the current frame
                // (MODCOD and frame length).
                double weightedOccupancy =
                    itFromMerge->second.back()->GetSpectralEfficiency(carrierBandwidthInHz) *
                    occupancy;
 
                double maxNewOccupancyIfMerged =
                    0.0; // holder variable during a maximum value search
                Ptr<SatBbFrame> frameToMerge =
                    nullptr; // holder variable for frame to potentially merge
 
                // check rest of the containers to find frame to merge.
                for (FrameContainer_t::reverse_iterator itToMerge =
                         ++FrameContainer_t::reverse_iterator(itFromMerge);
                     itToMerge != m_container.rend();
                     itToMerge++)
                {
                    // BB Frames currently exists in the BB Frame container for this MODCOD.
                    if (itToMerge->second.empty() == false)
                    {
                        /* check whether there is enough space in the frame */
                        // GetBbFrameLowOccupancyThreshold() returns a configured parameter. Part of
                        // a high-low threshold hysteresis damper. Current occupancy is no good.
                        // Need to fill in more.
                        double occupancy2 = itToMerge->second.back()->GetOccupancy();
 
                        if (occupancy2 < m_bbFrameConf->GetBbFrameLowOccupancyThreshold())
                        {
                            Ptr<SatBbFrame> frame = itFromMerge->second.back();
 
                            double newOccupancyIfMerged =
                                itToMerge->second.back()->GetOccupancyIfMerged(frame);
 
                            if (newOccupancyIfMerged > maxNewOccupancyIfMerged)
                            {
                                maxNewOccupancyIfMerged = newOccupancyIfMerged;
                                frameToMerge = itToMerge->second.back();
                            }
                        }
                    }
                }
 
                // check control message container tail still, if it is not empty and MODCOD match
                // control messages are used default MODCOD
                if ((m_ctrlContainer.empty() == false) &&
                    (m_ctrlContainer.back()->GetModcod() <= itFromMerge->first))
                {
                    if (m_ctrlContainer.back()->GetOccupancy() <
                        m_bbFrameConf->GetBbFrameLowOccupancyThreshold())
                    {
                        double newOccupancyIfMerged = m_ctrlContainer.back()->GetOccupancyIfMerged(
                            itFromMerge->second.back());
 
                        if (newOccupancyIfMerged > maxNewOccupancyIfMerged)
                        {
                            maxNewOccupancyIfMerged = newOccupancyIfMerged;
                            frameToMerge = m_ctrlContainer.back();
                        }
                    }
                }
 
                // frame found where merging can be tried
                if (frameToMerge)
                {
                    double newWeightedOccupancyIfMerged =
                        frameToMerge->GetSpectralEfficiency(carrierBandwidthInHz) *
                        maxNewOccupancyIfMerged;
 
                    if (newWeightedOccupancyIfMerged > weightedOccupancy)
                    {
                        // Merge two frames
 
                        if (frameToMerge->MergeWithFrame(itFromMerge->second.back(),
                                                         m_bbFrameMergeTrace))
                        {
                            m_totalDuration -= itFromMerge->second.back()->GetDuration();
                            itFromMerge->second.pop_back();
                        }
                    }
                }
            }
        }
    }
 
    // if both short and normal frames are used then try to shrink normal frames
    // which are last ones in containers
    if (m_bbFrameConf->GetBbFrameUsageMode() == SatEnums::SHORT_AND_NORMAL_FRAMES)
    {
        // go through all MODCOD based BB Frame containers and try to shrink last frame in the
        // container
        for (FrameContainer_t::reverse_iterator it = m_container.rbegin(); it != m_container.rend();
             it++)
        {
            if (it->second.empty() == false)
            {
                m_totalDuration -= it->second.back()->Shrink(m_bbFrameConf);
            }
        }
 
        if (m_ctrlContainer.empty() == false)
        {
            m_totalDuration -= m_ctrlContainer.back()->Shrink(m_bbFrameConf);
        }
    }
}
 
} // namespace ns3